Personally I don't mind children misbehaving as long as their parents are actively trying to stop it or at least keeping some sort of control over them. It's the parents/grandparents, who don't see anything wrong with their kids behavior, or simply don't care that really bug me. I've been working as a waitress in different places over the past two years, I think I've seen a good portion of brats acting up over this time. Fussy eater? That's fine. Overtired from travelling? I can deal with that. Overexcited? Great! Spilt your drink by accident? Adults do that too! Any good waiter/waitress in any type of restaurant, posh or gastro pub, can cope with this, and more, as long as the parents are doing their job. It is not appropriate for your child to be running around, free to do whatever they want in my place of work. Nobody would ever take their child to an office and let them do any of the stuff they get away with in a restaurant!
The milder cases of brats being let loose can be laughed over, but sometimes it can be just plain old dangerous. A normal well adjusted child will take any toys around to the table their parents are sitting at and play beside or around it. I remember one incident where I had children playing in the area where servers come and go to the kitchen. With heavy plates. Containing scalding hot food. That will burn them and crush their annoying little heads. Eventually their parents had to be asked to move them after we had said to the kids, several times to take the toys to their table, it wasn't safe to play where they were and my manager nearly tripped over them while carrying three sizzler plates.
Sticky fingers all over tables can be irritating but are easily cleaned up, most parents will clean up after their children with napkins provided or even wet wipes. Some will watch their kids make a dogs dinner out their meal, make a mess of the table and the floor underneath and not bat an eyelid. That's just rude. You wouldn't let your child do that at their own home or anyone else's, why should they get away with it in a restaurant?
Children that are too young to sit on a chair are normally in a high chair, you wouldn't think there would be any way of misbehaving with a chair... You would think that any self respecting parent would stop their young, fragile child from jumping up and down on the chair. I once had someone sit through their little boys tantrum as he used a chair as a trampoline, when he eventually toppled the chair over they waited for us to pick the chair up and said, 'Oh, that chair isn't very stable, is it?' 'Well, it's not really designed to be a trampoline, I'm afraid.'
Something that I really don't understand is when people let their little darlings play with their phones or video games at the dinner table. It's just so rude and then when we are trying to serve you or them, if the attention is on the gadget then our job is doubly hard. I really hate when 'tweens', teens or young adults have their phone beside the placemat. It's in the road and every time I go to clean the table, if there is mess around the phone I get a funny look or even a grab for the phone as if I'm going to steal it. This is the most insulting thing I have happen to me on a regular basis. I have my own phone, thanks, it's in my handbag. Where yours should be.
Being in a new environment is exciting and sometimes kids just want to run around and have fun. It doesn't mean you should let them though. I once had two boys who were just running around the place in a great big loop. It would have been ok, except that once we had more customers in it was annoying them as well as the staff trying to do their job. Another time I had a little girl trying to run through back corridors through to either the kitchen or the public bar. Neither place a very child friendly area. All the while her mum was to busy drinking wine and catching up with a friend to control her own child. I caught her running back and forth between both areas and was leading her back to her mum when she started to run through and, being vertically challenged, she ran into the corner of a table. I wasn't the only waitress to be happy to see them go.
It's not all doom and gloom though. Children with parents that look after them make all the bad experiences seem worth it. Tiny tots just learning to speak saying 'ta' when you give them something, mum's that clean up after their spawn and dads who keep a tight leash on their sugar crazed demons make all the difference. With everything you have to take the good with the bad. I still really want to have signs like this where I work though. I would totally enforce this.