Will I lose all user data when leaving Beta programme if running a stable build? I'm enrolled in the beta programme but currently running a stable build. The beta programme page states (when leaving the programme);


  Soon afterwards, your device will be sent an OTA update that will wipe all user data and install the latest stable, public version of Android


I would like to leave the beta programme but don't want to lose my user data. As I'm running a stable build, will my data be safe? I would hope that as I'm running the latest stable build I will simply not receive any future beta releases.
You won't lose your data. You'll only be sent a fresh build of Android that wipes your device if you're currently running beta software when you unenroll. 

I enrolled in the beta program on my Nexus 6P to get the finished version of 7.0 Nougat when it came out, installed it, and then later unenrolled while running the finished build of 7.0. My data was, as expected, not wiped.

tl;dr: Your data is safe, so long as you are running a finished release build (and not beta software).