Wobbling is banned in some tourneys because - provided flawless execution, that has been proven to be achievable by humans) - it's an inescable 30ish% to death grab. On the one hand wobbling doesn't make ICs the ssbm meta knight and doesn't really change the matchups against them that much since even without wobbling the stuff ICs can do from a grab is fairly unhealthy for the grabbed player anyways, but on the other hand there's nothing a human (or even a frame perfect player) can do against it, so quite a few TOs ban it.
Poof "mini-stall" is not banned because even with perfect execution there's a vulnerability window (I think Amsah mentioned .5 seconds). The difference to wobbling should be pretty obvious: you can't break the wobble even if you could do all the stuff in the perfect control videos. The shino stall has been proven to be interruptible by players.
If the risk vs reward situation is fair can't be answered by simply looking at percentages. To me it appears the only fair way is to look at the current meta game and see whether it's a viable tactic for shiek to shino stall after a lead till time runs out, and the only match where this has been used to some degree - as far as I know - was the Amsah vs Jman match (and even there time didn't run out, Amsah only forced jman to stop the laser camping), but if I look at other Amsah matches, he seems to be pretty reluctant to continue the stall if the other player approaches the ledge, so probably there isn't a problem right now.
The only reasons to ban a tactic in a game are (loosely based on a Sirlin article)
- the tactic has been proven to win games / tournaments
- the meta game is more deep / enjoyable without it
shino stall has never won games for a player so far, and it's not like banning it would improve the
current meta game.
To me the far more interesting thing to do in this thread would be discussing a way to break the stall ingame, not with arbitrary rules outside of the game (avoiding all unneeded rules is a pretty good way to run things to me, especially in cases like here where it's probably nigh impossible to put a hard ruling in place anyways.)
For my main hitting shiek out of it is far too easy to discuss actually... throw turnips / if nearby a downsmash might work fine, too :x )
Would shielding next to the edge > wavedash oos towards shiek during the vulnerable window > shine spike work for fox? (techskill is the answer to everything as fox, right? (: )
If every character (or at least the top tiers, since nobody (replace with "only axe") plays something else anyways

) has a viable answer to the stall, there's not much of a problem. And even if the answer isn't that strong and approaching shiek on the edge is giving her a slight advantage ... well... matchups aren't balanced to the 50 - 50 point for equal players before this, they won't be afterwards, and if shiek steps up some places in the tier list till a better answer is found, there's no problem to me (at least it ain't jiggly puff :D )