I had the same thought. Rather than try to control what is out there already, loosen up a bit and put your personality out there on the net. Blogging, tweeting, or whatever would counter your indiscretion by giving a potential employer something to compare to.

Additionally, would you really want to work for a place that would judge you for a single line in an obscure 'zine?

This is exactly what a lawyer would tell you--fair use is a defense and not a right. There's no mention of fair use in the Constitution, but rather the defense evolved in the courts over a number of years and was a part of the 1976 Copyright Act.

With that said, our common sense tells us it's a right. We hear about cases where fair use was successfully argued and we (I think rightly) feel that we can claim similar uses as fair.

The flaw in the system is really that that fair use defense might need to be re-argued in court, should the owner of a copyrighted work decide to be a "jerk" about it.