I've generally relied on Defender and "common sense", I just have a PC or two that tend to be focused on gaming, and I'm a little more conscious of how much poorly vetted software I run on them (things like game modifications running native code). Especially after a scare a year or so back with a game modification that had been infected with a key logger. I wouldn't really think to inspect something like that closely (and it had a large userbase, so even if I had searched around I probably would have figured it was safe)