During Scrapyard, Hackatime was mandatory, and was one of the biggest defining factors to HQ about the success of a satellite. So yeah, technically attendees aren't _forced_ to code, but getting the most weighted grants is still your biggest focus.
For those who don't know, HC uses a unit called "weighted grants" which supposedly equates to 10 hours of good quality work, in order to determine success. The issue is, the definition of good quality work is currently set as "most lines written", excluding R&D and the 20 other steps that it takes to design something.