The + trick is becoming well known with spammers anyway. I registered with one site as "[email protected]" having never used the "[email protected]" address anywhere and within a few days I was getting spam to "[email protected]" and "[email protected]". Whoever got that list of emails was clever enough to know to try removing the + portion.

Obviously you can never give out the "[email protected]" address and then assume that everything that goes to that address must be spam, but I've had legitimate contact from companies who have had to email me by removing the + portion because their internal email system wouldn't allow addresses with a + in them.