
I can't see the problem! Hours are left up to 6 hours some days ( :( bad I know) but I don't think they notic. I can walk for the door after being gone ages and they might lift their head just to see who it is, other times I can go up to the post box, come back, and you'd think I left them for days!!!!!!
Normally though mine are all asleep. During school hours in holidays they tend to be asleep anyway. I personally don't like leaving kongs etc about, just in case, but its personal.
As long as you don't necleat your baby there will be no problem