With YT, it might be an account-specific metric. Ie: flagged as a frequent sleeper. This would not surprise me, since they track just about every other metric possible against your account.

You can have multiple YT accounts on a single gmail acct, but I don't think that'll fool them. They know where you initially logged in from. So you will likely need multiple gmail accounts to do this kind of experiment.

Good shout.

They don't have SIMs, they'll be connected to a VPN router, and I'll create new Gmail accounts for each device, from each device.