Sgt_Kickaxe - 12:36 am on Jun 19, 2012 (gmt 0)
I wouldn't stress it, as long as you are not linking to the shortened urls I don't see why google would spider them in the first place
I wasn't stressing it, until I made some manual redirects and have a boat load of shortened urls being reported in GWT as 404, meaning Google had crawled them even though I never linked to them. It's not until I changed things that they showed up and if I had never made any manual changes I would never have known about all the shortened urls Google knows about.
After doing some digging: adding this to the sites functions.php file wordpress stops redirecting shortened versions of urls.