True. Arguing with a cop is an excercise in futility, and furthermore might get one into real trouble. The most prudent course of action would be to keep mum and take one's complaints to court. Trying to wag one's tongue at a police officer is walking on a mine-field, and it really doesn't accomplish anything (I've seen people go ballistic over a PARKING TICKET and get themselves written up all the worse).
However with that said 'tasering' a pregnant woman is absolutely dumb. Not only does it endanger the fetus (what is the PC word for an unborn baby these days ....I can't keep up with the Lib dictionary), but it also exposes the police officer/police department/city to legal ramifications. IT was quite the imprudent action, and you can rest assured that the lady in question will take some legal action (and that the city will settle instead of letting it go to court).
They in essence paid the woman.
Anyways, arguing with a police officer is never a prudent thing to do. Neither is it for a police officer to 'taser' an openly pregnant woman. I'd say both individuals in this case were asking for it ....the woman for mouthing off a cop, and the cop for giving the woman a blank check on the city's dime.
Both individuals were dumb. Really really dumb.
Thus, to paraphrase your rule. The first rule is as you put it: 'argue with a policeman...expect adverse consequences.' However i would add an addendum to that rule, specifically targeted at law enforcement, and it would go something like this: "Strive to ascertain absolute professionalism, legal propriety and adequate sagacity in all actions to ensure that you do not in essence start drafting blank checks to people on the city’s dime."
The cop was dumb for arresting her? If tasering her was part of the departments policy and procedure and they chose to skip that and force her to release the steering wheel by other means of force such as pain compliance or impact weapons, they would truly have opened themselves up for a whopping civil suit. Deviating from policy in use of force situations is a fast track to the courthouse. Of course people can sue over anything, but it is more legally defensible if the officers act according to established departmental policy.
As far as physically forcing her to release her grip on the steering wheel, it is nearly impossible to make someone do that without injuring them. Try it sometime. If an adult doesn't want to let go of a steering wheel, it often takes amounts of force that lead to sprains, broken bones, nerve damage etc.... Tasers and pepper spray are a step down from impact weapons on the force continuum.
Sounds like mom shouldn't have endangered her baby by being such an obstinate ass. The courts are there for a reason other than filing civil actions....