While I can't say I've ever changed my carry piece based on the perceived threat.
Oh wait I can, I normally carry one 14rd spare mag, and I swapped to two 16rd when I was going to repossess a car one evening. Also swapped the 14rd in the gun for a 16rd. But that's an extreme case where I knew there was higher risks.
I do change my carry around based on weather, clothing, and even my mood.
My two carry pieces are a CZ PCR and a Taurus 38 snub. While I carry the PCR most, somedays I just feel like carrying the revolver.
And how did you know it was higher risk ? Did criminals give you a call and tell you they would be active that night? And on lighter nights did they call and tell you they were going to stay in and watch a movie instead of deciding on attacking people?