For those of you who might have been wondering, the toll cameras on the ICC do in fact work.
I had a transponder read failure while driving there the other day (maybe a lane change while going through the gate is enough to do this) and got a letter in the mail from the Maryland toll collectors.
Turns out that I updated my EZ-Pass account when I got the Bolt... but forgot to update it when I got the vanity tags for the Bolt six weeks later. So they had a clean picture of the tag but no way to tie it to my account. Oops.