Well, leaving God out of this equation, Least, if she called me back saying the show was sold out, I would have offered her two choices:
1/I come get you now and you see it another day or night
2/You stay there and wait until the later show starts
This doesn't address your night-driving dilemma, but it does establish some clear boundaries IMO.
Let the girls pool their money together for a taxi, or get the other mom or dad to do the pickup since you did the drop off.
And I guess this is where God comes into it for me, because I am able to turn these situations over to my Higher Power. It doesn't mean I expect God to drive them home or anything silly like that, but it just means that I make a conscious healthy choice, and turn how it turns out i.e. how others react over to Him.