The question is not if there would be signs before a VEI8 erruption but if they would be recognized as precursors of a super erruption at all or early enough to be prepared when it happens.

Unrest is such an usual thing at big explosive Calderas, and there is no Data suggesting at what level of exacerbation the Volcano becomes realy dangerous (=Vei 7-8 imminent).  

Another point is the fact that a warning would have to be given pretty early in advance. If the unrests significantly increases just a few month, weeks or even days before the erruption it is too late, and warnigns that just suggest that a supererruption might be possible within the next ten Years are probably too vague to make so many efforts for getting prepared.