唔認同
同一個account 最多只係share 同一個credential用黎做 user authentication (by VPN provider)
VPN connection 既 encryption key 應該係create connection個陣既 key exchange 黎 share secret between VPN server and VPN client. 而呢個key exchange 唔需要知道 user credential都可以做到
所以理論上只有VPN server 同 VPN client (i.e. your device) 有個encryption key.