@Tamara ****************
right. I'd just get a 30 day extension on the entry you have now, then border bounce at Mae Sai - Tachiliek for your last 30 day visa exempt entry and extend that another 30 days too. That'd give you almost 90 days (30 day extension on this entry, a 30 day visa exempt entry and a 30 day extension on that entry) and just let the kids overstay from now on and don't worry about it at all. I mean if you wanted to you could bounce them in and out at Mae Sai to get a new 30 day visa exempt entry but I'd just let them overstay on the stamp they're on and leave them on the thai side while you bounce out and back in.