If you're LE, you don't even need to route data, just watch their connection. Earlier I was thinking about a potential correlation attack when the "vendor last online" feature is updated, but messaging them directly provides a more accurate time. All of this can be avoided with obfuscated private bridges (since you don't touch any part of the Tor network until after a bridge), or a VPN. While a VPN won't protect you if LE is specifically targeting you, discovering all the VPN users, given the large number of VPN providers in the world, and private VPNs on VPSes, and then analyzing all those users, makes a fishing expedition orders of magnitude harder.