In a closely followed speech a year ago, Craig Federighi, Apple’s senior vice president of software engineering, talked about Apple’s upcoming restrictions on the way advertisers can track iPhone users. Apple could yank apps from the App Store if they didn’t comply with the new privacy rules, he said.

It’s been seven months since Apple’s rules went into effect, and most iPhone users by now have encountered pop-ups asking whether they want to let an app track them while they use other apps or websites. The prompts have upended digital advertising and how companies use trackers to measure the effectiveness of mobile ad campaigns. But Snap and other apps with ad businesses hurt by the changes have launched new ad-measurement techniques that some critics say violate the spirit of Apple’s rules, making it hard to know whether Apple is prepared to follow through on Federighi’s threat.

So far it has not. Apple didn’t provide many specifics about the rules, so companies are unsure how to interpret them, including what kind of ad technology Apple deems permissible. Apple has been silent on the issue and hasn’t taken action against Snap, Facebook or ad-tech companies that have created workarounds, leaving the impression that it is OK with their solutions.