who reads signs around stations lol never really bothered because.. why would I? ......
This really sums your situation up quite neatly. Why should you need to read up on things, why can't you just jump in the game and go do stuff?
BTW your suggestion "...
just add another warning to rebuy respawn screen ..." and " ...
unless theres a better warning on the rebuy screen..." is rather moot - if you are in the rebuy screen then you either can or can't rebuy - if you can't then that is your warning.

If you have gone through multiple rebuys then you should know that it is using up your credit balance - or maybe you can't be bothered to read that either.
Really, seriously, stop digging - accept your mistake and get on with the game. The way things stand you can recoup just about any losses in a day even if you are flying a fully A-rated Corvette or Cutter - in which you should know about the rebuy.