I am admin for several lists hosted by sonic.net. I have recently noticed an increase in multiple simultaneous subscribe attempts by the same address across the various lists I admin. It therefore seems there is an automated attempt to subscribe to open public lists at sonic. While it's not (yet) to the point of wreaking havoc with my time to reject each one, it is an annoying hassle. I bring this for discussion here as my suggest to support.sonic.net to develop some sort of filter to spot this activity was rejected. They did advise it could become a future feature request if enough people complain about it.