I've seen a lot of what you've noticed, I don't have my own kids (yet) but I look after my nephew a lot when he's up in Brisbane from the Gold Coast over an entire weekend every month or so.

I can't say I've had your entire experience, but I've seen it at least three times. And considering the amount of time with my nephew (1 weekend in 4-5 at best), that gives you an indication how rife this issue is here.