Well, if they already have most of that data (ip/connection metadata from backbone isps) -- and the provider/target site is small enough that traffic analysis is enough to defeat the vpn -- all bets are off anyway. This is a basic problem with VPNs -- you need to assume all data going in and out is logged -- if you're the only one visiting omghowcanimakebombsforeal.com at any given hundreds of a second -- then you're pretty much done for.