Well.. I'm one of the guys who ended up marrying a student, so what does that make me?
In all fairness, though, when we met, we were both students, and were married before I received my yudansha and started teaching on a regular basis.
I think we do pretty good job of keeping our personal stuff off the mat, though we have certainly had to work through it at times.
I agree that "trolling for dates" at the dojo is not a good thing, but it can be hard to avoid in a university setting
That said, I don't think that either my wife or I were looking at the time... we got along well, and after knowing each other for a few months, I just couldn't help but ask her out. I think we were each old enough, too, to be responsible about it.