While the tone of this post was a little tongue in check, it is certainly the most likely answer. PayPal does send marketing/sales traffic on the same pipe as

While the tone of this post was a little tongue in check, it is certainly the most likely answer. PayPal does send marketing/sales traffic on the same pipe as their transactional traffic, which as expected ends up with lots of spam flags. ie I didn't ask for a line of credit. Side note: There are only 3 major webmail/freemail services left, so running afoul can be a very serious issue. Speaking about the postmaster level. GMail, Verizon, Microsoft Verizon might be bigger than Gmail at this point with acquisitions.