I would characterize the legal opinions we have received as "wildly divergent".
Some of the best discussion and counsel I have had took place during the EFF Canary Summit which was held at NYU in 2014. These disussions took place under Chatham House Rules, however, so I can't attribute it to anyone. Again, best characterized as "wildly divergent".
Of note:
rsync.net is, to a layperson, best described as a virtual safe deposit box. There are no abilities to publish, share or work collaboratively on data. In addition, an rsync.net account is relatively expensive. The kinds of activities that might attract a NSL or gagged order are naturally repulsed by these structural factors.
It's also a good filtering mechanism for non-technical clients, but I'm drifting off-topic now ...
See my response to your parent, upthread.
The canary already contains a list of all warrants we have ever received - it just so happens that list is zero items long.