From my knowledge there isn't any "Max Number of People Watching at Once" rule for my Crunchyroll account. I'm currently paying for the 3 month subscriptions for about a year now and going strong.
If theres anyone that's constantly waiting for premium passes, let me know. I'm down to share my CR account with some people so they can watch.
Only thing I ask is that you don't put anime's in my QUEUE or TO-WATCH list
Also don't judge my previous watch history LOL.