... without even making some effort to suggest that they keep the noise down 
I'm not talking about the odd noise but when mums happily chatting/ talking on mobile while their kids are screaming rraaaahhhhh stampeding over the chairs and generally ruining the whole thing for everyone else in there, why can't the mums just explain that there are some places it's fine to do that (eg park) and some where you could keep a bit quieter.
teaching their children to be inconsiderate IMO