I think any experts who know that the answer is correct should vote it up as a confirmation. For me, it will help me to decide whether I have to accept it as the solution or I have to wait for other answers. If the answer has enough upvotes then I am sure it will be the final solution.
If the experts just read it without giving any comments, how can I as the questioner know it is enough to use it as the solution?
What do you think? Does this policy make sense?