I agree with you @PerBonomi
Bottom line for us: the value of a solution is for the original poster, of course, but over time, for all users overtime. A user may feel funny about the solution marked by a mod and should have the possibility to raise concern, but it happens in a context where more solutions is better.
We're with @CyJervis on this. Our moderators are allowed to mark a post as solution accepted but only if the customer clearly indicates he was helped by the answer / solved his question.
We report on this regularly and our moderators only accept a handful compared to the big bucket of customers marking answers as solved. So far all good.
I am personally torn a little bit here. I think our process is good but I also recognize how some answers may be a great and correct answer and very helpful to anyone reading the conversation however by process we will not mark it as an accepted solution. I think there is much to say for ensuring great content is surfaced in your community and it may encourage other users to respond to topics. It's controversial and perhaps a challenge to manage. I will noodle on this myself a little more. (In the past our experts could mark topic as solved and that did not always go without issues....)
Recognizing that every community is different, there certainly will be some communities where the following logic doesn't apply. But due to the enormous value of identifying great, helpful answers in a community, as well as recognizing those who have provided that content (solution authors leaderboard), and knowing that it is common for the original poster to not come back and mark a reply as a solution, I would generally recommend that the following process be followed.
1. Allow time for the original poster (OP) to choose a reply.
2. Make use of the feature which automatically notifies the OP that their post has replies after a set period of time.
3. If Mods believe there is a reply that might be an answer, ping the OP and check, and encourage them to come back and choose.
4. If no reply from the OP, verify with Support, and, if verified, mark as Accepted.
5. Handle any objections from the OP on a case by case basis. They are welcome to post a reply at that point explaining their experience and what worked or didn't work for them.
I believe that following that process provides enough cover for the community team in case of objections by the OP, while not losing an opportunity to both highlight a great answer, and acknowledge the person who provided it.
Good suggestion @RobbL. There is also a feature I am hoping in brought over from the Jive-x acquisition that also addresses surfacing quality answers. I can't remember the specifics but if I recall correctly, you can allow replies to be marked as most likely an solution once it receive an admin set amount of likes/kudos.