It can't be done, IP address alone is a problem. And even if there's trust today, that could change at any time. I'd rather not have the lifetime chore of making sure I still trust something I never wanted to have to trust in the first place.

There's no truly anonymous telemetry, there's only anonymous until combined with other data sets. You'd have to only store and process aggregate records (like "# of users using feature of X") and never store individual records, but if your application phones home without my knowledge, my trust is already violated and I won't believe you if you say you only store/process aggregates.