Well, if any Wing Chun student gets in his mind that chi sao is anything other than a training exercise, he's in deep doo doo. He may not have a very good teacher, or perhaps he's just not too bright!
Chi sao is a fanatasic training exercise, but no halfway intelligent wing chun man would mistake it for fighting. Unfortunately, many people seem to assume that a wing chun man's idea of fighting has to do with trying to turn a fight into chi sao. Very silly. A wing chun man has no more interest in playing with someone's hands than anyone else. He simply wants to hit you. In the process, sometimes bridges happen. But they are not sought out specifically, or waited for. Quite the contrary. They're often the result of your own attack having failed! And who wants that? Like anyone else, a wing chun man would be much happier punching your face than having you block it just so he can establish a bridge.
Baguamonk -- I view wing chun as a very streamlined, sensible style that forms a solid base to expand from. Its clear logic and simplicity make it a very good core style that builds up some useful fighting proficiency exceptionally quickly. It's a great place to begin; and once you begin, you need to keep growing and learning other things too.
I would definitely expect to see anyone from any style have difficulty with things they were not trained in, and that would certainly include wing chun men having problems with shoots and the like. It's extremely difficult to handle what you're not familiar with. If the person applying it is expert at what you're totally unfamiliar with, then of course it's even tougher! Starting with jiu-jitsu myself, I was as out of my depth when it came to handwork with wing chun men as they are with chokes, throws, and such. Luckily, in today's world most of us have the freedom to eventually cross train in other styles without it being an unspeakable insult to our first teachers or being grounds for a challenge between schools! And I think anyone who doesn't is probably kidding themselves about how well rounded their understanding of fighting really is, as well as about how well their style will protect them from every kind of harm.