Whilst I can see the appeal of the 90 day route, not least because it could have ended this 18 months ago, the response if Unite and crew is an unknown. I expect Unite would try to seek an injunction. I also fear that some of the more cavalier elements of BASSA would discourage crew from signing with assurances that everything will be OK...
What is also worrying is that anything other than a strike ballot paper seems to be greeted with apathy by crew.