I think your situation is complicated by the fact that your sessions are free - you are not paying for them. This is where things can get quite muddled. If I were in this situation, I wouldn’t say anything at all. I would continue to arrive in time for sessions (or even early) and I’d use that waiting time to my advantage. I’d write in my journal, read a book or magazine, fiddle around on my phone, meditate, grade papers (I’m a teacher), update my calendar, etc.