The "Hacktivist" event triggers from Bill but in a very short timespan. If you get the first tip from Bill (bar), and then the tip about locker rooms, then most likely you won't get info about the hacking.
As suggested in a previous page, you must trigger the event at the very beginning of the game, the first time you talk to Bill he tells you about the bar, go to work at the bar and the next time you can have lunch with him (should be day 4 because there are some forced events inbetween) he should tell you about the hacking. Also make sure to have 1 or 2 computer points (obtained going into Class D in the afternoon).
For what I've tried (had to restart a game at day 71 with all events completed because this one was missing), if you go to him on day 4 with zero computer points, even if you're gone to the bar, he won't tell anything. I re-tried with 2 points and it worked.
And from day 7 he should start talking about the locker rooms, so hacking is really an easy miss.