I don't notice them avoiding traps at all. Today my party walked over a detected pressure plate, one by one single file. And I actually stopped them first, then clicked past the trap to move them. Instead going around it, it was click boom click boom click boom. And there was plenty room to go around it. He may have just said, "Everyone step on this!"
On the way out, they all stepped on it again.
Pressure plates are not avoided. This is because some pressure plates are helpful and you want to be able to stand on them.
It is however physically impossible to force pathing on a detected mine outside of combat. The pathing has to be set before detection... It's something I wish they'd change. It really is a lot easier to just walk mines with my fire immune character than it is to painstakingly go and blow them up so I don't accidentally walk on an undetected one while the party is together.
