I'm struggling to figure out what 'trail of bits' you think would be obviously and easily pulled together by an individual somewhere in the twitter infrastructure. I guess maybe someone who has access to activity analytics could maybe connect accesses to the anonymous account to accesses to another account from the same client. I suppose Twitter's teams who investigate malicious accounts probably have tools for connecting sockpuppets to their masters, which could be brought to bear. But it seems unlikely to me that the pool of people who have access to the tools and data to do this is very large, or that that group of people would not be subject to careful oversight to make sure their privileges are not being abused. The risk that people with this level of access will be approached by journalists offering cash for insight into celebrities (e.g. who is Justin Bieber DMing?) means you'd have to put controls around it.