Speedy Gonzales Strikes Again

It's happened again!
Without going into too much detail and also without assigning blame or judgment (only because i promised this in the intro!), it's happened again to someone i know.

Scenario
1. Guy meets girl.
2. Guy decides he likes girl. Alternative reality - Guy is of marriageable age and thinks it's time to settle down maybe because of familial pressure, or most of his friends are married and he's feeling left out, or maybe.... yada, yada
3. Guy says all the right things
4. Girl drops guard and begins to get sucked in as guy continues to go out of his way to do and say right things.
5. Girl falls completely and takes steps to convey that to guy.
6. Guy pulls a 'speedy' and takes off in the other direction pronto!

I'm still biting my tongue in order not to come across as judgemental, but the truth is i've seen this happen time after time, after time. And you know what? It's not cool! I really can't put it more eloquently than that.

However, as i have taken it upon myself to play Devil's Advocate and be objective, here are some possible theories as to why this kind of thing might happen.

No 1 Theory
The guy is an attention seeking, egomanical jerkwad who plays with the affections and emotions of unsuspecting women because it makes him feel wanted and he enj0ys the power that he is able to wield over these impressionable females

No 2 Theory
The guy really wasn't ready for a relationship or to give up his independence and things were beginning to get out of his control perhaps sooner than he thought they would, and the only response he could summon was to flee. It was the old evolutionary concept of 'fight or flight' and he chose to flee like a rat from a sinking ship.

No 3 Theory
The thrill of the chase wore off as soon as she said yes.

No 4 Theory
The guy was actually sincere and needed time to come to terms with the enormity of what he was getting himself into and just needed some time and space. Hypothetically, x days/weeks/months down the line he could have arrived at the conclusion that he really did want to be in a relationship with this girl, but....and it's a very big BUT....isn't it just a little bit presumptuous to think that you can ask a girl to (or rather, assume that a girl will) put her life on hold until such a time as you get your shit together and realise that you really want to be in a relationship with her.

I personally have always believed that the men hold too much of the power when it comes to relationships! I know others will disagree and say it's the woman who actually gets to choose who to be with. But what if she chooses a jerkwad (my new favourite word) who then decides he doesn't actually want her afterall, hmm? What then?

Is there any justification for a man to behave this way?
If yes, how could it better be handled?
What (if anything) can women do to protect themselves from situations like this?

Please discuss...