How to deal with people dropping dogs while traveling?

Hi, I have received a few requests by now asking for hosting a dog overnight while the owner is traveling. They want to just drop the dog and make no meet and greet. I have myself a dog at home and she is the most submissive non aggressive one, but I can't know about the other dog and their chemistry, so I was wondering what other people offering daycare or overnight service policy on this was. I wish I could put those request on hold but still get other potential business requests (I think the person can make several requests, so that is good on their side). THanks, Irene.