I consider instinctive action to be something that one does when confronted with an unusual circumstance, not the person's usual action, which for many player's is to slide into first base. See Derek Jeter's flip play or for contrast the non-instinctive Bernie Williams asking for directions while running the bases. However, I will not quibble about the definition of instinct. Let's just consider the actions of a player.
Players often do things that are obviously wrong. Sliding and diving when they are unnecessary are frequent examples. The other day Jim Thome slid into home plate and the catcher was no where near the plate; it was completely unnecessary. At least he slid feet first. How stupid is it to slide face first into the catcher's shin guards.
During my blogtalkradio program on July 27 it was mentioned that someone had done a study to determine whether a base runner gets to second base faster sliding feet first or hands first. Supposedly it was suggested that hands first may be faster because the players fingers are longer than their toes. Shoeless Joe Jackson actually wore shoes while playing MLB as do all players that I know about so toe length is irrelevant. When sliding hands first players stupidly extend their fingers needlessly exposing them to injury but actually seem to contact the bag with the palms of their hands.
Years ago when almost all players slid feet first they were coached to grab fistfuls of dirt to form a fist that would keep their fingers cupped to prevent injury when sliding. When batting gloves came into common use, some players removed the gloves and held them in their palms for the same clutching grip.
If players had any sense they would wear sliding bags on their hands. No, not mittens. Bags. There is no need for the thumb to be exposed. See Yankee Brett Gardner who recently injured his thumb sliding into second.
Many, if not most, outfield dives are unnecessary. Watch them carefully and you will see that. The dive often occurs after the catch or the ball is above the knee where it can be caught comfortably. Plus, there is no advantage to extending the fingers on the bare hand when attempting to catch the ball with the glove yet they all do it. All that does is needlessly expose the fingers and thumb to injury. See a pattern here?
Many outfield slides are also unnecessary. See Nick Swisher who recently slid feet first to avoid a wall that was thirty feet away and dropped a catchable fly that was FAIR! Swisher also makes little style jumps when he's about to catch a ball and that has contributed to his dropping a couple this season. This is in addition to Swisher whiffing on flies but I digress too much.
Players make mistakes. Copying those mistakes are mistakes.