This is not the same rule as your previously stated "Don't talk to men", worded in a scarily controlling manner.

They are very very different.

This in fact comes from a communication and trust again, you've talked about the problem of outside interference and trust each other not to get into those kinds of problems, mutually. This comes from respect, not the domineering and controlling thing you stated previously. In the event that any such problem should arise again simply talking about it and working against it is all that's necessary to get around it. That is a relationship, "do what I say <end of>" is not, one is a command while the other is an agreement.

What is the point at all Phil? Everything is based upon trust, if you don't have trust what is the point in the relationship?

Allow me to reiterate, creating rules motivated by fear of loss with the threat of breaking up with a person makes no sense whatsoever. Agreeing that certain things cause insecurities and simply respecting the relationship by not causing such problems (without ever having made any commands or rule) is the natural way in which this is usually dealt with. As K said, he does not put himself in potentially compromising situations because of the relationship - attempting to enforce this upon a woman is just trying to turn her into something she is not. If she's going to do that kind of thing just find someone that's better suited to you, don't attempt to dominate and control her instead.

Most people do run from this, I'm hypothesising but I think the correlation probably comes from authenticity viewpoint. People consider this period to be the bit where a relationship goes from just fun into something serious and committed. It would make sense that people want to be absolutely sure their partner loves them, (even the negative parts of them) before things get properly serious.

In that sense it's not necessarily born out of dishonesty, it's born out of not wanting to go forwards without full disclosure. Would it not be more dishonest to instead never tell a person? Do you fully disclose any of the things that make you fucked up before you even get into a relationship with someone? - I know a few somewhat insecure people who fall in love rather easily who do this, it tends not to work out very well for them.

There's a time and a place for the serious stuff to come out, it's when the relationship starts to become a serious thing. The early stages are all fun, play and light.

There's layers to people and those deepest layers are the last to come out, they are usually the things that have affected us most in life. Shaped us. Even if you've gotten over your horrors they are still there, they still make you who you are.