Apple Pay’s Express Transit feature is meant to make it easier and faster to use public transportation in markets where it’s supported. But it may be proving too easy for some users.

According to a report from the New York Post on Thursday, some Express Transit users in the New York City area are running into accidental charges from Apple Pay just by walking near OMNY tap-and-ride terminals. It sounds like some users are just getting close enough to have Apple Pay Express Transit finalize a fare purchase, even if they aren’t directly tapping their iPhone or Apple Watch on the terminal itself.

Express Transit is designed to be fast and simple. The user has already authorized a specific debit or credit card to handle Express Transit transactions, so users don’t have to use a passcode, PIN, Touch ID, or Face ID to authenticate a purchase. The default card is charged and away you go.

(Here’s how Express Transit works.)

However, this does not appear to be a widespread issue at the moment. According to the report, about “30 people” have complained to the MTA over “unintended charges when the Express Transit feature of their iPhones is activated”. The MTA’s chief revenue officer Al Putre says that the organization is working with Apple to address the problem, but, for now, it sounds like if this is a major concern for some users they should deactivate Express Transit until that fix is released.

So, not great news for folks who have run into this issue.