If you jump into a taxi and say "follow that car" will they really do it?

Try it and let us know how it works out.

Most likely 'not' - it would be a terrible liability issue for the taxi driver so, most intelligent, level-headed drivers who are looking to steer clear (haha) of trouble and not be in danger of getting sued would not follow that car. Of course, if you made an offer the driver couldn't refuse, maybe dropping a million dollars in cash in his or her lap - then 'who knows?'

The other possibility is you get an unintelligent taxi driver who has lost their mind - they may "follow that car" just for the fun of it with no thought that they could wind up in prison or bankrupt after a lawsuit or something else 'bad.'

No. That's because taxis aren't for following random cars.

If you get a fun driver, if I drove taxis I would do it it's fun just following people around

No of course they won't. Only in Hollywood my friend.