I just noticed yesterday bees checking out my swarm trap. There were about 10 bees flying in and out, flying around the sides and checking out the gaps.
I decided to put up another trap just in case my one hive is planning on swarming - that way there will be two choices for them - and hopefully one of my traps is better suited than anywhere else! Currently, the only thing in them is frames with undrawn foundation and some lemon grass oil.
Congratulations on your trap working. (And yeah, as others said, put in frames so they can make their comb on the frames.