The rules for disappearing from the afterlife appeared plainly obvious after how Sawashiro passed on as soon as she got to sing a new song on the acoustic guitar she adored, and how baseball guy felt really happy about being able to make the catch. Even the MC has figured it out by then since he runs up to the guy to try and stop him from getting over his lingering regret.
The way things are going, the choice about being stuck in the afterlife forever and hang out with friends or do what they wanted to do and pass on will probably be played up for lots drama later on, since with baseball guy it's obvious that the way to keep him around was to have him miss that catch and lose the game. Also, the MC's amnesia might mean that he could end up doing what'd obliterate him without realizing it if the show wanted to appeal to drama for the sake of drama, but I guess but it'd be okay if we got some hints about what his regret might be before then.
If my hypotheses end up being proven right, then I'd probably say that Maeda's writing here is a bit too obvious, but then again that'd be better than whatever mess Charlotte was supposed to be with all those plot twists and tone changes every two or so episodes after half a season of nothing actually happening.
http://www.crunchyroll.com/kyousougiga
