well ill give you a few solid reason.
coming from someone who has worked MANY years as an armed patrol officer with a private security company , i fully understand what you mean about the level 3 retention holsters. they work great. for what they are designed for. to ensure that YOU the LEO are the only person who can gain easy access to your weapon. i also understand the LEO stand on having your weapon taken from you and being offed with it. this is a thought that i guarantee crosses every one of our minds every time we holster our gun and leave the house.
i am also a holder of a CCW. and i both CC and OC. depending on the circumstances i will either CC or OC. i usually CC, i will admit. just because i enter areas where there are crowds of people who are elbow to elbow and as you mentioned, i never want someone elses hand on my weapon. now i do carry my glock 32 in a serpa holster, wich gives a small level of retention , and not everyone knows how to use it so that brings some peace of mind. but when im that close to others i prefer to CC just to minimize the risk.
now OC is a different story. when i do OC its usually for comfortability. if im in my car, obviously in a dangerous situation it would take some twisting, removing of the seatbelt, leaning forward removing cover clothing to gain access to the weapon, which can take some time. time that i may not have. so i ALWAYS OC in the car. just because as you as an LEO can grasp your weapon while seated and draw it, i like having the same oportunity to defend myself easily.
I also OC at work. i work at a summer resort at the beach. usually 100+ customers playing tennis, vollyball, eating icecream and having fun. most o which are regulars who know me by name. i Oc at work for my safety and the safety of our guests and it really does deter people from causing problems.
i also oc on night walks around my town, its a bit rough and has a rather high crime rate and i've personally watched people who looked less than desireable cross the street and walk on the other side when they see my firearm. not to mention i have yet again easier access and a 1.3 second decrease in draw time when i OC.
i also OC due to heat. my concealment holster is an IWB leather open top rig. with no retention. and working outside in the summer i tend to sweat *as we all do* this causes moisture to get into the leather and contact whichever weapon i may be carrying at the time, causing rust, pitting, or tother un happy occurances to the finish and function of my investment. when i OC i do not have this problem.
i can see both sides of the arguement. OC could result in being made a target. in the backs of our minds we all know this, however the likely hood of it happening is such a small fraction of a whole number because of the fact that we are armed. Criminals work on a risk vs. gain scale. small risk, large gain= good to go. huge risk- small to no gain= no go. the fact that not only are they risking jail time, but potentially death from attacking the carrier, or anyone in the area of him or her, will most likely always outweigh the potential of a monitary gain or possibility of success in the attempted crime.
and you also have to take into account as an LEO. when you were trained to carry and use your firearm. the training did not just stop there. you were also trained on how to KEEP your firearm, and how to defend it by other means if neccisary and how to defend it with other means of lethal force if called for. as you were trained we also train ourselves. we are not your "average" armed citizen. we are not the type to run to the gun shop. pick up a 9mm , throw it in a holster and say "there im invincible now" , most of if not all of us train extensively, as much if not more than most LEO's do on a regular basis, a lot of us carry less lethal weapons as backups, and alot of us also train on weapon retention, and hand to hand techniques in general seeing as our weapon is a last ditch effort, any one of us would go toe to toe with someone who attempted to disarm us before we resorted to our firearms. so us being "joe shmoe with a gun" is not a truth at all. we take great responsibility in carrying what we do. we take great caution and alot of training to make sure that the weapon that is in our possession stays in our possession.