It does seem logical, but it adds a big cost structure and bureaucracy to sell, monitor and otherwise administer the program. I'd be for user fees if they added LESS THAN 5% to the costs of running whatever it is they capture fees for. But I bet that's false, but admittedly that's a guess.

You have to choose between two bad things:
* User fees, with the requisite overhead (as above) AND plain old annoyance factors
* A general fund of tax revenues, where "politics" decide budgets for things

It's easy to complain about BOTH of these, the question isn't if they have flaws, but which one of these two you prefer.