The guidelines are very nuanced and reviewers are free to interpret them as they see fit. We have had an app in the store for over 2 years that jumped through hoops to avoid the 30% Apple Tax to accept a charitable donation in app. Our Apple account Rep reached out to our marketing director in the fall of last year to tell us the policy changed and that we wouldn't have to do stupid shit anymore. So we spent Nov and December developing a much improved experience. It was submitted, approved and has been available in the store since before Christmas. This week we received notification that our app violated the guidelines with regards to that specific feature and we had 2 weeks to fix it.