Al, if you check out similar threads on UMGF, you'll find that a lot of people, for various reasons, don't want a strap button on their Martin (they play sitting down/they like the strap attached to the head 'cowboy-style'/they feel it detracts from the guitar's monetary or aesthetic value/ etc., etc., ad nauseam.

I guess not putting one on is Martin's way of giving the player the freedom to choose.

Me? I always put one on, on the treble side of the heel (a la Taylor (spit)), most comfortable for me.