The only thing that worries us is whether it's "too" aggressive. So, if you have mail that's not getting to you, please do let us know as it's possible the anti-spam protection is rejecting it. The user at the far end will be getting an "bounce" error, however if you can provide their email address we should be able to look into it from there.

Although we have had problems with this method before (being too aggressive) a couple of the big boys have now adopted this scheme, so I guess everyone will be in the same boat.