Which means that no one is marked "of the elect" by Baptism or the "Sinner's Prayer" for eternal heaven. Apparently, God judges us on things that happen in our lives BESIDES that one event...The first installment doesn't guarantee future ones.
Regards
From only the human POV, the elect are marked at regeneration. Some say the sinner's prayer falsely, as the article I posted to you, after your post here, shows. On your side, I don't know how or if people are "falsely" Baptized. You know how I feel about (infant) Baptism, but of course that doesn't stop the Catholic elect from later coming to the saving grace of Christ (perhaps at Confirmation, an idea I like). At that point, the Catholic "COULD" have assurance, but of course this would never happen because the person would have to throw out Catholic teaching. :) Not happening!
So, for either Catholic, Orthodox, or Protestant, the mark is ACTUALLY there at the time of faith for the elect. Whether any of us can or do know it is a matter of difference. Our view is that, for the elect, the first installment DOES guarantee the future actions.