When you say you caught two swarms within 50 feet of the hives, are you saying you; 1) You caught two swarms with a trap. or 2) You caught two swarms by knocking them into a box?
Almost all swarms land and regroup within 100 yards and eyesight of the original colony. So yes, all swarms will be found close by in your own beeyards. But this is from where they send out scouts and decide to fly to the new location.
That location may be a quarter mile away, or a trap located in a tree next to your hives. It all depends on how many locations they find and which they decide upon.
IF GIVEN A CHOICE, bees will select one away from the beeyard. And one with as many items as noted on the list of the link I provided.
So the point is to make the traps as desireable as possible. They may move into a swarm trap or head off to greener pastures. The more traps they have to choose from, the better your odds. the more other locations they have that fit the criteria, the less likely you will have to catch a swarm.
My main yard over at the farm, has little trees or structures in the area. I caught about 10 swarms hanging on bushes this year. I also caught 4 swarms that moved into equipment 25 feet from a row of hives and under roof of a pole barn.
I would not be putting ANYTHING on the comb, which might deter bees. You might be protecting the comb, but you might also be limiting your chances of a swarm.