The cheap cardboard box swarm trap

On the internet was a video of how to make a cheap swarm trap.

You get a cardboard box that a ream of paper comes in - any company office has these - and you put a frame of drawn out comb in the box, put the lid on and tape it shut. I put 2 frames of drawn out comb in mine - taped a piece of cardboard over the one hole - the way the box is made, there are two holes, one on each end right towards the middle top of the box - perfect for a bee entrance. I closed off the one end and had the frames in a v shape, with the entrance end where each frame was in each corner and angled to the back closed off hole. The guy didn't get into details on how to waterproof it - so since I work for a company that has plastic wrap for wrapping truck pallets for shipments - I used it. Wrapping the box completely and then cutting the hole out and taping around it.
I put this swarm trap up in a tree stand and had noticed it started getting attention right away.
I kept checking everyday and at first there were just a few, and each day it got more and more where sometimes there were up to 20 bees flying around.
Then all of a sudden - it got to where there were just a few - a one flying in, one flying out, one at the entrance.
I put my ear to the box and could hear bees, but no big hum and no weight to the box.
Today I went to check it and noticed that the box was starting to look damp. At first I thought water must be getting in, but then I remembered the guy in the video saying once you catch a swarm, you can't wait too long to take them out because they create moisture which destroys the box. Could it be - did I actually catch a swarm?
I went back to the house to get a flashlight, and once back climbed up to peer into the hole. All I saw was bees, so regardless of the weight, I had a swarm in the box.
I got the box down and took it to the bee yard to get transferred to a hive. I cut the plastic wrap, but the tape holding the lid of, and peeled back the lid. There on the lid of the box was two sections of newly drawn comb with a very small swarm, so I picked up the lid, put it over the hive and jolted it. The bees fell into the hive, I took out the two frames of already drawn out comb and put them in - and put the lid on. I added a frame of honey just so they have something to eat.
It's plain to see it's a secondary swarm, and they will have to be helped along - I'll keep adding capped brood in to help their numbers build up more quickly - but it's still exciting to catch a swarm in a trap - even if it is just a small swarm.
So, the cardboard box trap DOES work - but if you notice your box looking wet and saggy - and you have it waterproofed, there is a good chance you have caught a swarm!