As a general rule across the web, I'd agree with you. Although, I feel like on StackExcahge (or at least SO) those with the highest scores typically gave good answers in their domain as judged by their community and would not commonly give any answers outside their domain that could be voted up simply based on user rep alone.
I don't really have any hard data on this, it's opinion based on seeing extremely good answers from high rep people regularly, and not being able to recall seeing poor answers from high rep users voted highly when they aren't actually useful.