Bed bugs don't just magically appear. They are brought in by outside people. Yes they group crew rooms but mainly for logistical reasons and placement. I know at my airline our rooms are usually at the end of the hallway where it is more quiet. Also airline crews don't have usual check in and out times. From a house keeping perspective it helps to group our rooms. And bed bugs happen in all hotels. Doesn't matter the best or middle of the road.