http://dkn255hz262ypmii.onion/index.php?topic=77808
http://dkn255hz262ypmii.onion/index.php?topic=151488
Those are just two of the many, many threads discussing this. He is free to access SR how he wants, and Liberte is definitely a great set up, but why leave the .to in there when it's just as easy to remove it and not have to worry about what info is or is not available to the .to site owner? It's easier and simpler to remove it and not take the chance. I'm not just saying that for his benefit - because obviously if he's running Liberte, things are pretty secure, but I'm saying that because most people browsing with the .to in the url are NOT running Liberte or anything else for that matter -- most are simply browsing from the clearnet using the .to proxy to access onion sites. And for THOSE people, yes, it is dangerous.
EDIT:
In fact, the .to proxy site itself warns users:
By using this service instead of connecting directly to the Tor network you are trading off security and anonymity for convenience. Know that we can identify the IP of visitors using this service (but chooses not to). We strongly recommended to access Tor Hidden Services directly using the Tor Browser Bundle to increase your security and anonymity.