Problems we need like a hole in the head....

The NYT reports that

A new technology being used by produce distributors employs lasers to tattoo fruits and vegetables with their names, identifying numbers, countries of origin and other information that helps speed distribution. The marks are burned onto the outer layer of the skin and are visible to discerning consumers and befuddled cashiers alike.

Shanna* surmises that there might be a problem with cutting/peeling through these letters on Shabbat -- but is there really a halachic problem here? As far as I understand it, the writing is simply engraved onto the fruit (in fact, removing the outer layer of skin) and there is no other substance involved here -- unless I misunderstand the way a laser works. Anyone?
(Not that a negative answer to this question will necessarily prevent someone, someday, banning fruit on Shabbos, as Shanna worries. On the "plus" side for the Kashrut authorities: now there's an easy excuse to issue hechsherim for fruit and veggies!)

*Who got the story via noted the story was also mentioned by Dovbear