YS, will only work if you're in the same bucket. Ie...if you have 5 days remaining and there is someone in the 4 day bucket, they'll still give it to the 4 day guy, even if you YS. Except in a few rare cases, IMHO YS are practically a waste of time. With all that is going on, even if you get it, there is a high probability that one of the other pilots will need a landing as well.