> If not, what made this part of their university life?

The fact that he likely included his academic affiliation on any papers he wrote, likely used university resources to conduct or discuss some part of the research (e.g. meeting rooms, his office, his office phone), is an employee of the university, etc.

I mean, come on - no IRB is going to let you claim a technicality like that. If you could skirt around research regulations by just claiming you were doing it "on your own" with no affiliation to the university, the IRB would be effectively pointless.