Yuck! I just stayed in a very nice hotel this past weekend. I didn't do the flashlight trick, but I did keep all clothes and my suitcase, far away from the dresser and bed.
I admit that I have the guilty pleasure of watching "Billy the Exterminator" on A&E. One of the episodes I recently watched had to do with a personal residence with an extreme infestation of bedbugs. They were literally crawling over the bed and the ceiling, and almost covered the folds of the curtains. That REALLY had me itching and scratching.
I enjoy shows about bug and parasites, but this one definitely had me waving my hands while saying "Ooh! No way!!" and "Yuck!!" along with a few expletives. lol
I don't know how the occupant was able to live with them, except that maybe he didn't know just how bad the problem could become.
Last year I fought and won a 6-month battle, no stratch that - WAR- against those vermin vampires after moving into a new apartment. People who argue that they don't carry disease so we should just live with them obviously never had them. (And to them: FU, this is not a third-world country yet!) Yeah mosquitoes are more dangerous but you can seek refuge in your own home. With bed bugs, there is no refuge. You aren't safe in your own bed. If you start sleeping on the couch, they will find you there, too. They disrupt your sleep and rob your sanity. They must all die.
So yeah, take precautions because they are hell to try to get rid of (but NOT impossible!) If you do get them, either buy mattress encasements, or if you can't afford those...go to Home Depot and buy plastic sheeting and multiple rolls of duct tape. Triple tape everything. Get a professional exterminator and keep calling them back as many times as you need. Ideally you should throw out your couch but if you can't afford it have the exterminators spray inside the couch. Caulk everything. Wash all linens in hot water daily and dry TWICE (heat kills them). Vacuum every day if you can. Use diatomaceous earth every place that you can't caulk, every place where they might try to get in, etc. It dries them out and kills them. Don't rely on one method. Use everything.