If you find yourself without time to go from Condition 3 to 1? Then you need to work more on your situational awareness. Not that hard to see potential.
I'm not saying there is a RIGHT or WRONG way to do it. Israeli military carry in condition 3, many times our own military is taught the same. Not an all bad way to carry, prevents a lot of accidents, and can slow the gun being used against you cause many criminals are also criminally stupid. It all comes down you how you train, if you train...
I'm all for CCW, but I've met so many "mall Ninja's" and "Range Commandos" talking tough about their "Carry Strategy" while displaying their tricked out 1911 Yadda Yadda only to then watch them Yanking the trigger, have no stance, no practice, no skills whatsoever... It's like watching a first time rider on a Busa... Just embarrassing and sad.
So, TRAIN as you plan to FIGHT, I'd say that's most important regardless.
The chances you'll ever need your CCW are extremely slim, the chance you'll NOT recognize the threat ahead of time is even more remote still... However the chance you'll panic, jerk your weapon out of it's holster and shoot yourself in the leg while carrying in Con1... Pretty darn good given the amount of time folks actually spend training, practicing, and drilling with their weapon.
QUICK IT'S an EMERGENCY, You draw your weapon, jamming your finger into the trigger guard, yanking wildly you then mash the SLIDE RELEASE fishing for the safety, crap your pants and pass out from the exertion... Bad guy steals your gun and wallet... Giggles at your twitching prostrate form and moves on...
Not with a Glock