casino says quick spin plus spacebar looked automated, like what

Had something weird happen. I did a session on slots, not even turbo mode or anything, just spinning as quick as possible and hitting spacebar every time. Next day, I get an email that they're investigating for "automated play" because my spin rate was “unnatural.” Been using the spacebar for years, it’s way easier on my hands. No scripts, no macros, just clicky fingers.

Can they actually tell the difference between a fast human and a bot? I know the rules say no automation, but if you’re just good at keeping pace, are you at risk? All I did was try to grind through a bonus as fast as possible, not trying to game the system. Anyone else ever had this?