[alexmat]

As a spammer, wouldn't it be trivial to just run a regex on email lists looking for that pattern and then harvesting the results? Or is this like the old joke where you don't have to outrun the bear, just your friend?

[Tepix]

Well, one more reason not to use gmail i suppose. If you have your own mailserver you can configure a different delimiter.

[zingmars]

Sure, but then you get 100 other problems that come with self-hosted e-mail servers that might not be worth the hassle.