I disagree. If you can’t merge into a lane without taking up someone’s safety zone, then you don’t have enough space to merge. If the car in front of you wrecks, you have eaten up the reaction time of the driver behind you, greatly compounding the damage; especially for you, who gets front and rear ended.

The rule I was taught is: if the driver behind you has to even touch their brakes, you don’t have enough time/space to merge.