Enforcement while driving is extremely rate in CA. I've had 2 BMW and now a MY. The first BMW had no front plate at all, never an issue in 11 years. The second was a European delivery, so they insisted on the plateholder in front for Europe (drove it there for 5 weeks), so, since it was there anyway, mounted the front plate. Never an issue
Now with the MY I bought a quick bandit, but don't use it (keep in the back with plate on it), except:
*) When stopped for it I will say "Oops, forgot to put it back after car wash, I'll put it right on". That should avoid ticket (regular or fixit)
*) When going to San Francisco will put it on (SF parking enforcement is notorious for ticketing for this), but will avoid going to SF due to an epidemic of Tesla rear triangle windows break-ins.
*) When going into certain parking structures, ditto. There are not many of these enforced ones here
*) May also be a problem in HOV lanes, I'll find out (of course will have transponder and stickers).
BTW. The sticker problem is solved by ordering a cheap PPF kit. Made for the stickers. Stickers go on PPF, PPF on the car (which otherwise doesn't have PPF). Easy removal later on.