When you check into your room, peel back the sheets. Check along the edges of the mattress, where the binding is. If you see any spots of 'dirt' you may have a problem. See, the issue isn't really about cleanliness. It's the fact that people put their clothes away, then put the luggage on the floor, or beside the bed. The little critters can be in the furniture, so your clothes could carry them home. Or the little critters get into the luggage and ride home. Then, they are deposited at the next spot. They would qualify for some hefty frequent flyer miles!!!
My dd's camp had an issue with them last summer. They had a pest person come in and infumigate, but evidently it didn't completely work. When my dd's session started, the bugs were spotted three doors down from her room. The kids were all put into a field that night to sleep. All the beds were tossed out, into a huge bonfire and replaced with all metal bunks, with new mattresses!!! I can tell you that dd's luggage stayed in the garage, with her clothes. The clothes went directly into the wash, and then high heat dry!!!! No problems.