[noste]

It's doesn't seem to be that common, but not it's not unheard of either. For example, Amazon Payments prohibits "occult materials"[1], and according to an old Boing Boing article, Google Checkout used to prohibit "occult goods" as well[2].

1. https://payments.amazon.com/sdui/sdui/helpTab/Amazon-Flexibl...

2. http://www.boingboing.net/2006/06/29/google-launches-pred.ht...