Back when I waited tables, I once had a small family in and I took their order. While they were waiting, I noticed that they had moved tables and went to find out if they had been sitting in a draught or whatever to see if there was a problem.
Turns out the child had vomited all over the fully set table for four - full cutlery settings, side plates, wine glasses, cups, condiments, milk, sugar. It was dripping off the tablecloth onto the fabric of the seats and onto the floor. Spewed. I've cleaned up plenty in my time but this really got my stomach churning.
The mother just nonchalantly went "Oh yes, DD got a little sick, so we moved seats" and not only made zero effort to clean up, (which I always used to nicely tell people there was no need to anyway) but never so much as offered to. Dad just smirked. Child looked utterly miserably ill, the poor wee mite. 
I would have waved off any parent's attempts to clean up that with a wipe, - it needed sanitising properly after all and certainly would not have been anything other than understanding and kind about it, but the way that the mother pretended to ignore it and Dad smirking at me cleaning up the mess on my hands and knees and not even apologising was hugely disrespectful.
I'm a plate stacker and will do what I can to minimise the clean up for our waiting staff. And my child knows how to eat nicely at a table and not throw food.