Unfortunately, many people misconstrue the meaning of the accepted answer and think it is some sort of indication of quality. It isn't. The accepted answer is just and only the answer that the OP decided worked best for them. However, the OP is very often not an expert and can end up choosing a poor answer to accept. This is a well known issue that has been a problem on SE for many years.
And, in fact, we are finally getting a change that will improve that:
Unpinning the accepted answer from the top of the list of answers
SO has already stopped pinning the accepted answer to the top, and other sites are following suit (here's the relevant post for us: Would you like to have the accepted answer pinned or unpinned on UNIX & Linux?).
All this is to say that there is no benefit in having the community add a fake "Accept" mark. We already have a way for the community to mark the answer they consider best: upvotes. So instead of looking for the accepted answer, just look for the one with the most upvotes. This is, of course, also not guaranteed to be the "best" answer, but it is slightly more likely than just relying on one person's (the OP's) opinion which is all that accepted answers are.