Being that I am the Pets Hotel for my family, I never really have that problem. If anything their overweight, under exercised pets lose weight and get the exercise they need while here. My nephews and niece have all been raised with pets so they know how to be gentle to them, with the exception of the one time my youngest nephew about to sit on top of Chip thiking he is like their lab.
We did have an incident last weekend when they were here and on their way out the door. Which at the time I had my cat, my two boys, my sister's yorkie, and my other brother's cat. One of my nephews was holding the front door wide open. I could see all the animals inching towards the door, and I yelled "CLOSE THE DOOR!", luckily there were no escapes before they closed the door.