Only thing bad about showing your plates is you advertise what mods are done to your car and unscrupulouse people will be able to target your ride to steal and part out. I don't worry about it that's what insurance is for
To combat those who are against it I will bring up the fact of your talking to a stranger about your car at a show and looky their your plates are on display. So...
Who would you be more worried about some one on a computer or some one within 10' of your car?