Bookworm is correct I cant think of any occasions where the weather boxes you in to that extent, unless of course you have pushed on for too long. A 180 almost always does the trick.
I suppose there could be a greater risk of this happening when running through somewhere like Mig Alley where there is only one way in and one way out in terms of CAS.
I can think of more than a few occasions on the other hand when IFR a turn for weather avoidance seems sensible.
I recall recently dodging the CBs around Southampton and some particularly heavy downpours when the controller seemed intent on vectoring me through the worst of it.
Interesting when a CAT at the same time wanted to be vectored so far to the west he had to be warned that he was about to leave CAS.