They will get round to it.
No they won't, at least not in NY and NJ and probably other states. A bill specifically made it illegal to issue speeding tickets for speeding between toll plazas was enacted in NJ not long after EZPASS was installed. I believe a similar bill was passed in NY.
People have been saying what you said forever...and the moment they enact that, 75% of the people go back to paying cash. The road authorities make a dollar or two every month per transponder, they won't jeopardize their revenue stream.