Riding DC's Metrorail was a breeze. I bought a day pass and off we went. When you ride the Metro, you put your ticket in the slot and it pops out the top of the turnstile (similar to MARTA in Atlanta). They also don't use bars for their turnstiles, but a two-piece contraption that makes in impossible to slide through without paying. If you hop, you're likely to be spotted by DC finest.
This is the cool part; you also run your card through to exit the train. The system knows how far you traveled and reduces your card accordingly (since it is a regional rail system and fares vary). It also is another protection against people hopping the train.
If your card has a set dollar value (vs. paying for one day), it will tell you how much money you have left on your pass.
Everybody that rides DART knows that sometimes they take your ticket on the train, and sometimes they don't. Here's a thought:
If DART is in a revenue shortfall, maybe they should consider banning the honor system and collect everyone's fare upfront. In all major cities in which I've traveled and used rail, no other city works on an honor system. In fact, the only system that I remember that worked on an honor system was in Rio de Janiero, Brazil. On the bus in Rio, you board the bus at the rear door and they actually had a guy in one of the seats with a cash register drawer that made change.
Turnstiles on DART trains would make sure that everybody pays and save DART the trouble of having to walk through the rail cars and take tickets. I realize that some stations would need some reconfiguring (Lancaster-Kiest, White Rock, etc), but start with Mockingbird and a few others and see if the revenue starts to increase.
What do you think?