OMMing, is an Official Middleman that will assist to the trade and help to make the trade safe. There is Official Middleman's and Middleman's. The difference between them is that Official's went through a rigorous process before obtaining their rank.
In fact, the original account owner will always be able to recover it, as the most important thing when recovering an account is being under the same IP you had when you created the account.
For sure, it's safer if a middleman or an OMM does a recovery test, which will prove if the seller is the original owner or not, but still, the test can fail, for multiple reasons beside false information.
Your best option would be to buy from a trusted member of the community, otherwise, there is always a chance that the account gets recovered.
Hope this helped you.
