But if you ask a telco to give you data on a number that Google Voice administers, would the telco be able to fulfill that request? I mean, obviously they could

But if you ask a telco to give you data on a number that Google Voice administers, would the telco be able to fulfill that request? I mean, obviously they could with a little digging, but would their middlemen be able to? e.g. if my "real" email account is through Yahoo, but I tell the public about my GMail address which autoforwards to Yahoo, it wouldn't be straightforward (though it would be obviously possible) for Yahoo to deal with a request stated as "Please give me info about the email account, danspublicemailaddress@gmail.com".