If someone has an appointment, and arranges for a babysitter to come to watch his/her children while he/she goes to the appointment, and the babysitter doesn't show up, so the parent misses the appointment, and needs to book and pay for a new appointment, is the babysitter liable to pay for the missed appointment? Sources please.
I discussed this interesting case with my rav. For now, I can supply a partial answer, as we need to research some its nuances a bit further:
When you refer to a baby-sitter, it depends if you have "hired" this person or not. I.e. - if you pay this person on "salary" for him / her to come regularly or even as needed, then that person is in the category of a "shomer sachir" - a paid watcher. That person is responsible for negligence, which MAY include such "incidental" damages as not showing up on time for the appointment and causing you a loss.
Again, we need to research further, but, I placed this as food for thought, for now.
Poel yachol lachzor aphilu ad chatzi yom. A worker can backout even mid-day. You can't buy people. However you may be able to withold wages, even beyond the missed time. checkout the 6th perek of bava metziah