Which data centers are opted-in by default on a paid account

Hi,

I have configured various accounts and found that one had almost all data centers opted-in, another was missing a few, and another had only two data centers opted-in. I don't know the reason for the difference, whether it was configured in the past, or because it was previously a free account. May I ask, assuming the user has never changed the setting, are all data centers opted-in by default on paid accounts? This is important because I have seen a user connected to a data center on the other side of the globe, which could have been the reason for two disconnections during an important meeting.

Thanks in advance for any help.