The only time DH has 'banned' children from our house they had (on Xmas day):
Opened every jigsaw gift to my DDs - several as they loved them. All jigsaws had to be thrown away as multiple pieces were missing.
Stood on the back of my leather sofas despite being told by me not to. Literally as soon as I turned my back they would do it again. Eventually ripped the zip so badly I had to superglue it.
Broke several ornamental gifts, torn dolls clothing, headless doll at one point (fixed but forever weakened and soon thrown away).
Refused to sit for dinner, made to sit for dinner (the mother piping up that I really had spoken to them overly firmly). Ran off as and when they wanted.
Towards the end of the day, when I hadn't checked on them for half an hour as we'd been clearing up after dinner, DD1 (then 6) came into the room in tears and said 'I can't stop them.' We knew it was going to be epic.
The 2 of them had thrown all of the contents of a reception room into DD2's bedroom. DVDs and CDs scratched as they'd been taken out of boxes, the paper inserts ripped, CD cases pulled apart and mostly broken; Books (!) thrown with pages folded and ripped. My ornaments chucked in and some chipped. They'd opened cupboards and taken the contents out to do this including the one with crystals and bits that I sell. Have you ever picked up £1000 of tumbled crystal gemstones and checked them over for damage? It was all mangled in with many balls of yarn from my hidden wool stash.
Their mother was ready to take them home and even her eyes widened at the 12+ inch depth of detritus in DD2's room. Not kidding. It was a foot between the top of our possessions and the carpet over a double bedroom sized room. I plastered on a smile must have been a tad manic and assured her it was nothing and ushered out of the house. Shut the door when DH made his announcement that they were never to return.
No fear of that. Apparently the next day the 'friend' called a mutual friend whinging that she'd been lonely and no one had seen her all holiday. Her kids then took that friend's house to pieces on Boxing Day.
If you're still reading OP... I think a few wotsit hand prints after non-direct instructions is a learning curve on setting boundaries for guests. If your DH really thinks this is a problem I can get him in touch with a potential new friend (she needs them) with kids that will show him what ban-able kids look like.