AIBU to think if you have a 14yo babysitter looking after your DCs, that you take some responsibility for making sure they get home safely & if you are running late, you make sure you get home first before telling them to organise a taxi for themselves?? 
Just that really, I genuinely don't know what would be the norm. I only know if I had someone elses 14yo DD looking after my own DCs, drunk or not, I would make sure I organised them a cab on getting home & make sure they had enough money to cover the whole fare.
This is a regular job for DD. First time worked well as the family held their own taxi back for her & DD came home in that.
Since then its been disorganised & stressful, one week DD went out to get the cab she thought was outside, only to find herself stuck out on a dark street & no cab, family having quickly gone to bed, meaning she rang us pretty scared & DH had to go get her.
This week, they ring DD to tell her they are on their way & to ring a cab as they will be home in 5 minutes. The turned up 20 minutes later & DD was anxious as cab driver was annoyed & she was £7 out of pocket for the fare.
Its not safe for her to walk home alone & bar the first week, its been a similar stress every time
AIBU to think this is a bit crap ???