I agree children are more mess! We recently had guests with one child of about 6 yrs of age for 3 nights and it took much longer to clean up.... There were crumbs, etc all over the place. But I have to say the the parents weren't necessarily careful. Instead of putting sheets on the futon, they just used blankets .... which meant that in addition to the regular sheets laundery, we now had to wash blankets.....!
I charge an additional $20 per extra guest over 2 people, that way we don't get a lot of guests who want to use us as a crash pad /party place.
We've had really good luck so far, only one that I wish I'd made a bad review.... I didn't review her but she didn't review me either.
We are considering making a HOUSE RULE that only signed in guests are allowed (children would be included with parents) since this is our home and we live here, I don't want people I don't know coming and going...... Most people don't abuse but every once in awhile you get a wingnut I suppose.