"He's in a nutshell!"
"What's he doing in there?"
etc.
For a serious answer, see below.
First of all, characters optimised like this are unbalanced, and suck in every situation outside their area of expertise. They are, frankly, no fun to play.
Explaining this to any wouldbe munchkins will often moderate the problem, although it won't eliminate it.
Specialisation as such, though, isn't really a problem. Look at the characters in Firefly, for example. In any case, standard Traveller characters tend to end up as specialists anyway. Navy characters are rarely much use in gunfights, for example.
The main controlling factors, however are maturity and character conception. Maturity is obvious enough - you can't legislate against munchkinism.
Character conception is the real key, though. Before you design a character, you should always sit down and work out who and what the character is. That will, in turn, determine what skills the character would and should have, and which they won't.
The referee has a veto on this, and at all other points during the design process. This means that the referee can not only block abuses, she can also help guide the players towards building interesting and balanced characters.
The real secret of point-based chargen is that there are two participants in the process - the player and the referee. The process is essentially one of negotiation between the two.
Random chargen downplays the referee role - but he still plays a role. It also increases the role of the "third person" - the game designer.
Any character created by any system is created by committee.
Now, back to brief character descriptions: you describe a character according to their character conception. In many cases, that would be equivalent to the way you would describe them in a career/term based system. "My character spent twenty years in the Navy and became a Captain".
Or it could be: "my character was experimented on in a secret government laboratory, is a bit nuts, apparently psychic, and is alarmingly good at killing people". I'm not sure that I would allow this character, though...
