Sony cameras do have built-in temperature warnings, and will shut down if they get too hot (even without this hack, see recent reviews for the new a6300, lots of overheating issues with it). My old Sony NEX-5N would give me overheating warnings and shut down when I did too much consecutive video with it as well.
I'll run my hx90v for a longer duration and see if I can get a temperature warning/shutdown to occur. I'll plug it into a power source so it will record longer than the life of the battery. But I got about an hour and a half of continuous video out of it yesterday without any issues.
Update: I plugged my hx90v into an external USB battery pack and hit record. The results: It recorded until I ran out of space on my memory card (64gb). Almost 3 hours of continuous video recorded (2hr42min59sec to be exact). The camera didn't feel hot or anything like that.