Yes, we used the huge fireguards over our radiators .. the drips and runs are probably still embeded on them ..
I'm not sure carrier bags would be a solution though (apart from the children not being allowed to handle plastic bags themselves !!) ~ the coordinating of small bodies/hats, coats, newletters, other art work, plus the normal after session chats with parents would probably end up with everything being dropped forgotten & trampled on (OOo I'm having flash backs
LOL !!)
Utillising any heat generator that's already in use, is a good way to make sure sticky work dries as thoroughly as possible before heading home.