Put new mac-addresses into an "Unknown" profile?

Since our teenager found out how to change Mac-addresses on his computer the parental-control and Blacklist is useless. 
As soon as his Profile hits "BedTime" he changes the Mac-address on his computer and happily continues to use the network. 
A solution could be that all new devices needs to be confirmed by the Admin, or all new devices is automatically put in a Unknown or Default profile with time restrictions. That way it would be of no use for him to change the mac. 
I've read the same issues on other Deccos as well. Is this a feature that you plan to implement, or do I need to go for other vendors?

Best regards 

Johan Samuelsson