In an earnings call this week, Gary Norcross, president and CEO of FIS, was asked whether or not banks are going to charge customers for access to mobile apps or wallets.

Several FIS clients "are charging and actually doing quite well with adoption and penetration," Norcross said, according to a transcript made public by Seeking Alpha. "The consumer is going to push mobile and some of these new transformative mobile channels, and so the result of that is financial institutions, like a lot of things that they've done historically around charging for certain types of accounts or certain services, they're going to slowly move towards some type of a way to monetize that channel."

The trend Norcross is referring to is one we've been tracking for some time.

Although some in the industry feel it's reputationally risky to charge fees for mobile banking services and argue that mobile is an inexpensive channel than branches, others appear to be having success charging fees for certain mobile conveniences.

U.S. Bank has been charging 50 cents per mobile check deposit since 2010 and the bank has said its adoption numbers are strong.

Regions Bank charges for remote deposit capture. The bank lets its prepaid customers load funds onto their cards through the mobile channel and select from a range of funds availability options. The funds can be available immediately for $5, overnight for $3, or after the standard processing time for 50 cents. While the bank has seen some backlash on social media, very few customers who have complained have actually left the bank. And more than a third of customers are choosing options that cost $3 or more.