I don't use vents with mine and every swarm I have caught and left in the trap for a period of time has sealed off all the cracks and crevices. With that said, this is only one variable in the equation. A trap with vents may still offer the best option for them.
Here is an example of one. Check out the propolis they packed around the seam of the cover blocking off any ventilation from under the top.https://www.youtube.com/watch?v=MMTlWYMcQoU#t=166