1EB with only 30k users, thats a wild TB-per-user ratio. My frame of reference; the largest storage platform I've ever worked on was a combined ~60PB (give or take) and that had hundreds of millions of users.
But yes at LHCb we discard about 97% of the data generated during collisions.
Disclaimer: I work on LHCb trigger system
33TB per user is a lot, but is it really "wild"? I can fill up well over 33TB of pro-camera photos in less than a year if I shoot every day. I'm sure scientists can generate quite a bit more data if they're doing big things like CERN does.