For everyone else’s edification, here is the reply from SlideME
"We provide our own in-app billing SDK and we support the OpenIAB SDK: http://slideme.org/developers/iap
We only permit in-app billing from Google Play or other markets if it is for non-essential virtual currency; that is, it must be completely optional and obtainable in-game so that users without Google Play are not complaining they cannot purchase it due to lack of premium currency (virtual gambling games such as poker, slots, bingo, lottery, betting, blackjack, etc are not granted this exception). SlideME may determine that this virtual currency usage is unacceptable. Any other uses, such as unlocking features, purchasing premium-only items, removing ads, upgrading the app, real or virtual gambling currency etc., are not permitted through external market billing and will cause application Denial. You’re limiting your monetization capability as many SlideME users lack Google Play services on their devices, and cannot make any purchases or downloads from that store with their device. Simply disabling in-app purchases but leaving the buttons in place will result in application rejection. "