Have you ever been tempted not to pay a fare? I imagine this will largely depend on the nature of the transport system you are using. In Paris, the barriers to enter the Metro are full height, so no chance of dodging them. In London, Underground barriers are about chest height, so probably too high to get over. In Warsaw, on the other hand, the barrier is only a turnstile, which I have seen jumped over (or slipped under) many times. Would a simple solution such as broader barrier stop this from happening? I’m pretty sure!