I've owned this MacBook since 2015 and have never had any issue with Siri randomly popping up for no reason. I'm not even saying "hey Siri." At first I didn't realize it was Siri - I was watching a YouTube video but, the audio kept dropping out. Eventually I saw the Siri message at the upper right corner of my screen asking what I needed help with. I never use Siri with my MacBook - just my iPhone - so it's okay to totally disable Siri on my MacBook if that's possible.