That is a great idea!!! We do pay DS14 occassionally for babysitting, but have not suggested it for this situation because we do not wanting him have the mindset that he has to actually take care of them (splitting hairs, I know, but it's all in the eye of the beholder, right?), rather, since he is *there*, they are to take care of themselves and he will make himself available for emergencies. Our backup plan is our neighbor in the case that DS14 has to stay after school/etc, the details of which has already been hammered out with the neighbor (she agreed to be available at HER home next door if DS is delayed and the 10 and 8 year old need anything at OUR home, for no compensation, because she will not be watchiing them at all, and if that doesn't work, then I can work from home the rest of the day).
DS14 is good with our general family understanding...the kids pitch in and help out when we need them to, and anything above and beyond will be rewarded in a variety of ways - for example, in exchange for doing extra chores that he normally wouldn't be required to do, we just paid $1200 for DS to go on his (optional) 8th grade class trip to Wash DC. He was required to "earn" $200 toward it by doing the chores/babysitting of our choice. The funny thing is, with him, is that as much as I am so careful about the babysitting thing, DS14 BEGS us to let him watch the kids for cash LOL. So it works out all around!
Maybe the next goal just might be saving toward Disney again!!!
