They should be slightly more explicit, but "...before the e-mails are accepted and reject anything that looks suspicious..." almost certainly means that spam is rejected with a 5xx message - or goes to your InBox, but is never accepted then hidden from you in a spam folder.

It's a good approach, and from a legal perspective I'm surprised more systems don't take this approach, because legally (at least in my local jurisdiction), you're deemed to have received an email when it "enters that information system" - i.e. when your SMTP server says 250.

This stuff matters quite a lot in the formation of contracts.