Airport taxi in US dollars

My daughter will be flying down to meet me on Playa Ropa after missing the last 3 years. In the past, I always let her know in advance how many pesos she’ll need for the private taxi ride from the airport. (I see it’s currently posted as $680). She makes sure to have the correct peso amount, but has said that the drivers often tell her they prefer US dollars. (What would the US dollar amount be these days?) Also, they ask for a tip after she pays them. This message board seems to encourage the use of pesos over dollars in general, as well as not expecting to tip on simple taxi rides. What shall I tell her?

DON'T pay in dollars! And do NOT tip them unless they actually do something besides driving the car to your destination without getting you killed.

Why do you seem adamant about not tipping unless they do something extra?
For the first time I had a woman taxi driver take me 'home'?
I guess I got carried away. I tipped her simply because she smiled at my jokes...