I am now aware that there is a possibility of releasing an IP from this rule. But I learnt this the hard way! I sat through an outreach session where we encountered blocking of IP and the participants were very disappointed because they could not create their usernames. There is another mail from Subhashish which echoes similar experience.
By way of working on this document and putting together small tips like these will make sure that others don't go through this pain. I'd encourage everyone to put their thoughts/learnings
here so that all of us can benefit out of it and make our outreach sessions more effective.