I've been lucky and only had a couple of Old Senses moments, one of which had the potential to get really ugly.
Back when I was 18-19 I used to do occasional pest control on a friends/bosses farm with my airgun, a Weihrauch HW77 (this is back in the UK). I would bait a patch of the open end of his storage barn with treats and lay down in a ditch across the way in my home made hide and shoot rats all day.
So, I've been at it a few hours when I hear a loud, firm voice telling me to "lay down my weapon and put my hands behind my head". I'm about to jump up and holler something about never taking me alive (my friends and I used to yank each others chains with "cop voice" all the time) when I get that feeling and just do exactly what I'm told.
Good thing I did, because when I'm turned around to see who's issuing orders, it's two cops with MP5's, as some tresspassing "rambler" had called an Armed Response Unit to deal with a "man in camo with a gun" they had seen lurking in the bushes. Which is annoying as I was rightly on private land, so the only people who had a legal right to be there were me, the landowners and the police. My boss got everything sorted out, but I swear, if I hadn't gone with my gut....
The other time was here in the US, when my wife and I lived in a sketchy apartment complex in a crappy neighbourhood. I woke up around 2am one night, sat bolt upright in bed and had the weirdest feeling. Our dogs weren't making a sound (chihuahuas make pretty good alarm systems) and I couldn't hear anything wrong but everything just felt wrong and I was totally awake, which is weird for me as I take -forever- to wake up usually.
I decided to give the apartment a once over, just in case so I got my SKS (all I had at the time) out the closet and my flashlight and checked all the doors and windows even though we lived on the third floor. Nothing was wrong, but I still had that twitchy feeling, so I camped out on the couch for a bit, in the dark with the rifle close to hand. My wife never even woke up (she's a heavy sleeper, has to be to live with me!) and I didn't get back to sleep till gone 4am, but I didn't mind missing the sleep one bit.....