FA - I think that is the crux. Weather is fluid, it changes, and in our systems, can change pretty rapidly. The pilot makes hopefully balanced and intelligent decisions, based on past experience and what he knows. Obviously there are times when we get caught out, however, if a pilot has gained, and used his IMCR then that should get him home.
I used to fly long distance VFR, down through France and Spain, and got caught out once. I came home and immedaitely got my IMC plus night. I then used that rating as much as I could - legally.i.e. I still check weather at departure, on route and at destination. If it looks crap, and I do not, or cannot, file an IFR plan I do not go.
In a sense the IMC does not fully fit some conditions, hence I am studying for IR. My decision. The rating has definately made VFR transit for me safer, in that you can go on top, you can descend knowledgeably through or up through layers. Again, where it is legal to do so.