It may have been that, as a Count, Corvus was best placed to protect the guild from the watch. Had he not been erased from history at that point, he could have personally aranged Lex's transfer to Anvil in his capacity as Count.
I do find it kind of funny how a well to do count is also a lowly Robin Hood thief. Then again, in-game it does seem hinted that his wife is a bit of a philanthropist herself, generally trying to give the homeless some kind of shelter and "job", even if it means sitting in a warehouse making sure rats don't get in.
Which just got me thinking. Maybe the reason why the TG is pretty Robin Hood is because of the GF's infamy. Unlike other grandmasters of other areas, they don't have the supposed infamy the GF does. This means they generally can intermingle with society and guards can't do squat, because they can't prove anything. GF, on the other hand, needs to be kept out of sight at all times, but he needs to know what is going on so he doesn't fall into a bad situation. This means he has to win the beggar's and poor people's trust. And to do that, he needs to make sure they're pretty well cared for, so he goes after those who are very well to do (i.e. the rich and merchants).
If he didn't have so much infamy, the TG in Cyrodiil probably wouldn't be so Robin Hood-eque. But that's my wishful thinking.