Hi Deckman:
Thanks for your efforts to bring traditional music to young people. I'm glad to hear there's funding.
As much I'm 100% in philosophical agreement with NOT changing the lyric, there is perhaps a little more to consider. With elementary & middle-school kids in mind...
You don't want to undermine your own efforts by being remembered for one unfortunate(?) word. "A man sang old songs at school today" is good. "A man said 'horny' in a song at school today", not so much.
Also, things being what they are in the good ol' USA, I wouldn't go near even the most vaguely questionable terminology around young kids where it can be avoided. Only one parent, teacher, student or administrator has to decide something was inappropriate, and you're (potentially) done. They'd be wrong, and the whole mess would be stupid, but the problem would be all yours. It really doesn't take much to get some folks worked up.
And, there's an excellent workaround in "thorny" (courtesy of gillymor, above). Much as I hate to say it, there's some merit in considering a change. Save the "real" version for less immature audiences, and avoid the distraction altogether. Hard enough to win over new fans of traditional music as it is.
Food for thought, maybe.
~Chris