In Toronto (Canada) our transit is free for those 12 and under. At first it caused a fair amount of fraud because adults were using the kid's passes. Easy enoug

In Toronto (Canada) our transit is free for those 12 and under. At first it caused a fair amount of fraud because adults were using the kid's passes. Easy enough to get around: kids don't need to use passes now, either. There are Proof of Age cards for the kids who look older than 12, though. Adults can't usually take advantage of that, so apparently that has solved the problem.