Proposed Change: When you hop alias' a cool down like if you had sent a message on an alias is placed, for 15 seconds, in which period you can send messages, which will append the regular cooldown for that onto the 15 seconds. At the end of a 10 second period, your old Alias ceases to be registered to your SIC, and you cannot receive messages from it. At then end of 15 seconds your old alias disappears, and you can change alias' again. Which would start the 15 second cooldown and process again. The key feature to this is that the old alias you were on only disappears after that fifteen seconds are up, and you can even receive messages from it for the first ten seconds of the cooldown.
In my mind this would go a long way to preventing people from immediately assuming someone is an alias hopper. And also allow a little bit of proper non-small world gumshoery, if you were to try and send to them at the last third of the cooldown and get the rejection notice.
It would also reduce the amount of Alias hopping to send threats then swiftly alias hopping back after the cooldown without much of a chance being given to react to the other player.