Reflecting on my season, where I primarily targeted foxes & coyotes.
All of my catches came from sets with bait - dirt holes, buried bait sets, and hay sets with bait.
0 catches on flat sets/scent post sets using only lure or urine.
I ran 50/50 baited sets and flat/scent post sets.
All on good locations, often 1 of each set type at each good location.
Always blended my flat/scent post sets well to keep them as natural as possible.
I read a lot about the effectiveness of flat/scent post sets but I didn’t see it this year despite a consistent effort.
What’s the deal?

Next year just might be different. The weather I think can make the difference also. Were you using the same lure at your different sets or did you change it up between the different type of sets?

Where I'm at when it comes to catching foxes and coyotes it depends what time of year it is.

During deer season its hard to trap anything because of the guts piles on the clubs and leases. I mainly catch them on blind sets.

There is a time right after deer season that dirt holes work great. The gut piles are gone and they are trying to fatten up before breeding season.

Flat sets/scent post work late January through March. They are looking for each other and it works. The key is to put them where they are traveling.

That's what works where I'm at.

Hard to beat a good bait. Real winter meat fed urine is hard to beat too if you can get some. Looks like you got it figured out with the bait. Keep doing what works.

I’m not sure where you’re at in PA but my numbers are opposite. 60+% come from flat sets and I’ve never really caught what I’d consider a big/old coyote in a dirt hole

I tried to use a different lure at every set on my line to limit redundancy.

I’m in central PA, a bit west of State College. Are you doing anything unique with your flat sets? I tried some different variations of flat sets and they didn’t seem to get much attention or action.

I'd ask how many catches are we talking about? Only a handful of catches could be too small of a sample size to really make any conclusions. I do as a whole find flat sets a bit tricky to control foot placement. Only good urine is worth using and there's more not so good urine out there than good. Might consider testing your lures in the off season and make sure they consistently get responses and commitments. Ive tested some pretty popular ones that didn't meet my standards.

I’ve experienced this many seasons. Bait sets were the ticket one season while post sets and flat sets were the better catch rate the next. I always run at least a pair of sets at each location and one is always a bait dirthole other will be a post set and if a third it’s a flat set. If the locations warrant I also like a couple snares for good measure.
I don’t get to trap very long most years so my catch rate needs to be good. The snares have saved my butt on catches many times too. Rainy, frozen and muddy conditions some years I was really glad I had the snares out. One year my best location during season of heavy rain and lots of mud was a simple log crossing. I caught more coyotes off of that log with snares than at any other set of location on my line. Originally set it for cats but after coyote #3 it was starting to be obvious what we needed for snare type and loop size and height there. That one log was a winner over any coyote set I had out that season and was a total fluke I even put a snare there in first place. But it was a good way for animals to cross the swollen creek.
Same on my coon line I run a mix of footholds, DPs, cages, and 220s or 160s. Bait sets, blind sets, and body grips and cages. Had em go right by DPs to end up in a 220, and was glad I had the variety of tools an sets.
I’m a firm believer in a variety of sets and tools at locations and that helps my catch rates.
Jim

I make a point that from January on to run a good straight gland with a quality urine on all post sets i make and usually set 2 to 1 posts to hole sets
i have recently discovered the effectivness of a quality concentrated urine and only using a couple drops as opposed to a spritz

At what point does a canine realize the lure down the hole isnt bait?

Usually right after he steps on the pan

Volume makes a difference. A mediocre formulation can sometimes get better attraction in a larger volume than a better formulation in smaller quantities. Seen it a good bit while testing. I dont think will ever truly understand how a canines sense of smell works. We know its much stronger than ours but I also believes it conveys information in different ways than ours

" my season" Oct/Nov or Jan/Feb?
Big difference for this observation.
Use a big bunch of bait early and
you well be the possum/coon king.

There is a lot of bad urine and lore for sale.

"All on good locations" Are these "lured" locals
200 yards apert or 10 miles apart?
How far do you think these foxes & coyotes range?

Go to the state rondy. Find Bob J the mod on here.
Buy 2 of each flavor his bait. With a sharpie X out the
word bait and write lure. Buy some pee from Bob too.

By the time those are used up you will be
past this and on to the next stage of "why".

Fresh sign and boot milage trumps all this other voodoo.

Try blue pipes with carp

I made a goal to put in more flat/post sets this year to give them an honest chance. I was blanking on them all until a little over a month ago. 6 of the last 7 coyotes I’ve caught have been off those flat/post sets with just urine and gland lure.

They have made a believer out of me.

Some trappers are pros at one type of set. They rinse and repeat. Others like to vary sets and smells. The learning never ends.

Try to keeps notes. I’m not good at it, but it helps especially when you are just getting started.

Enjoy the process and make more sets. Always more sets.

I’d heed this Wright Bros guys advice. Apply this to next seasons project and I’ll bet it’ll fly!