Question: Is there a way to enable any warning/message when the license count reaches the maximum number of seats?
Answer: Via System > Configure page (only visible to On-Premise Customers), you can enable a checkbox that will display a warning when the number of machine ID accounts reaches the maximum number of agent licenses:
Applies to: All VSA's - http://help.kaseya.com/webhelp/EN/vsa/9050000/#248.htm