Say someone hacks the db, is the problem easy to guess table names? The column should never have be called "passwords"?

Perhaps 30 years ago that would sound good.

Obscurity should hardly ever be a line of defense. If it is the only defense the problem isn't that it wasn't obscure enough.

Edit:

I'll do you one better. If you so much as suggest that obscurity is good security you actually openly invite people to fool around with your applications. The odds holes are to be found are much better than elsewhere.