[QUOTE=mikebg;11636545]
I was not refering to this, but the Israeli Chief Rabbinate requires all local rabbinates to use only 'gush katif' style bug-free produce. I am not sure what the position of the Tamam supervision authorities is with respect to this.QUOTE]

If only you were correct on this point, but you are not. Manufacturers can use any type of leafy vegetable they want and most have only "regular Kashrut" for lettuce and cabbage based items. In fact it is very, very difficult to find Mehadrin cabbage salads on the market as practically none of the large manufacturers have it.

Caterers usually use only "gush Katif" as it is logistically easier to use only one type of vegetable

Even the more stricter and more widely accepted local Rabbanute such as Jerusalem and Rehovot will give two types of Hechschers, Mehadrin and regular, which in part is due to the type of vegetable used.