For people Sam’s size, any type of pesticide would be devastating. If they get caught by surprise, they’d die. If they caught wind of the pest control before it happened, they’d have to relocate. Even after pest control is gone, the little guys live deep in the nooks and crannies of the motel so there might be poison lingering in the area that could either kill them or cause long term health complications and when you’re that size and have no access to a doctor, that’s something you’ll want to avoid.
Of course, relocating is a danger all on its own.
If you want to read about the little guys of mine that lived in a motel that did get hit by pest control, check out the following fic: