I know gmail has amazing spam filters, but even I wouldn't tempt fate like that.
I've had slashdot display my email address in clear text in every comment i've made here for years now. I've never received any mail to firstname.lastname@example.org (gmail lets you add a "+whatever" to your email), and i very rarely get a spam message in my inbox. These days, with so much email being spam, i don't think that being coy about your email address is really a valid strategy anymore. You've got to give it out to use it, and who knows what the heck the people you give it out to are doing with it?
Update: 01/31 at 22:01 GMT by KD : Google has now posted an explanation, apologizing and taking responsibility for the "human error" that led to the problem.