yep i guess it all depends on what part of the world your in, which mfg your dealing with.
In my 40yrs in this business i've only seen maybe 2 cases where inhouse techs at an outside company were granted access to mfg software, and there was a limited use policy in place as well, their software was not a full version, they only had access to the diagnostic side of it, all other funcationality was disbled. In this case it was with diagnozer (cat diagnostic software) and i think it was a test program they were doing with this customer. And during the time i was servicing this customer they had a breach in security due to one tech at one of their facilities handing out the passcode, so they had to change the access method. If i remember correctly they eventually discontinued this.
In my experience most mfg's are going to be resistant to giving it out to a non-dealer.