First I want to state that this was a VERY small test so these results are by no means meant to show the bigger picture. I was just bored and curious.
All testing was done on the (Auto) North American servers mostly late at night (after 5pm PST).
I ran 10 raids on reserve. 5 during the day and 5 at night. I went in each time with low/medium gear (Vepr hunter, penis helmet and lvl4 combo rig). When I spawned I would find the closest "off the beaten path" spot I could find to sit until the match timed out. I tried to make sure I was sitting in a spot that needed to be hard checked, but also had another angle opposite of me that required a hard check as well. I would not move at all once I was in position. I had one run were someone probably saw me get into position and found me pretty much right away so I didnt count that run.
5 daytime raid results: I was found and killed all 5. All 5 deaths were to PMCs.
3 times I was killed by a grenade through the window/door without ever seeing my killer.
1 raid a guy ran straight to my position and hard checked my angle without clearing any other angles first. Head shot top of head with first bullet.
The last death a guy walked into where I was and started packing mags or something before noticing me in the corner and killing me.
So 4 out of 5 deaths were suspicious for the daytime portion.
5 night raid results: I was found and killed in 3 raids. 1 death to PMC 2 to scavs.
The 1 PMC killed me by throwing a grenade where I was sitting without me ever seeing them.
The 2 scavs seemed to wander into me while looking for loot only noticing me after being in the same room for a moment (1 missed a whole ak mag before realizing I wasn't moving and he just knifed me).
The last 2 raids I timed out. Nobody killed me. I heard footsteps very close a handful of times both matches, but nobody found me.
1 suspicious death for the nighttime portion.
TLDR: I was killed in suspicious ways 5 out 10 raids. No hard data was gathered as my sample size is far too low, but it was a fun little experiment.