I understand it's not up to your (or anyone's) level of belief, but I am in intimately familiar with their modus operandi.
For everyone in the industry it is le secret de Polichinelle.
I think they don't sell their VPN data, because if that ever came out, that would destroy their business. Selling the data would be far too risky for them.
I think they don't sell their VPN data, because if that ever came out, that would destroy their business. Selling the data would be far too risky for them.