Cameras can record faces, match them up with public databases, including facebook, also can count exactly how many entered/left the facility
However, they are not cheating at the voting booth, they ‘rats are too smart for that, they cheat at the mailbox with the absentee ballots. Its just too easy to tamper with them, change them, toss out the ones that are not in your favor, etc. And in some states, you can go door to door to collect them and fill them out as well.
That is why Democrat registers, going around registering people at fairs or whatever, are also registering you to vote absentee, so if you don’t put yours in the mail, they will get it from you in person or make one up to substitute yours.
That is how they are stuffing the ballot box.
In some areas of California, the Mexican Mafia requires residents to request absentee ballots, bring them to the appropriate personnel who assure that the ballot is filled out properly and signed by the voter. The voter complies because he wants to make home and not end up in the hospital or morgue.