1. If you are pilot
Don't disturb other pilots
2. If you are ATC
Don't disturb pilots. Your service is only for pilots, who want to use it.
3. Multiple Connections
No! Please connect only once with your account. If you are ATC, you should not connect as a pilot with the same account, if you are pilot, you should not connect as an ATC with the same account.
4. Multiple Accounts
You may have up to 2 accounts, but you will need 2 email adresses to sign up.