its a training day for players who've never been involved in a tacsim/milsim game.
slightly longer version:
a few other groups do this, not just us. It became a requirement for new players, if they wanted to participate in PDW events (PDW being my team out of Regina). There's a different mindset to skirmish play vs milsim. And too often, we get players with the wrong mindset, playing the game. At our bootcamp, we try to give people some exposure to tactical play, and what is expected of them on the field during such an event.
Its not to say that milsim is better than skirmish, or vice versa. Its that when me or any other game planner, spends a few months trying to plan an event with specific gameplay in mind, it really pisses us off when some person figures they can just waltz in and "rambo" their way through the day. It also screws the experience for the other players who want to play milsim that particular day.
It doesn't seem much, to stir a man's soul. Just a moth eaten rag on a worm eaten pole. But 'tis the deeds that were done 'neath this moth eaten rag, when the pole was a staff, and the rag was a flag.
CUM CATAPULTAE PROSCRIPTAE ERUNT TUM SOLI PROSCRIPT CATAPULTAS HABEBUNT