Show me any example of "guerrilla marketing" that doesn't take advantage of some system. That's what makes it "guerrilla". This example is no less guerrilla than SPAM itself.
I'd assume guerrilla marketing should add some value to the message, thus helping it stick: it either makes you think, surprises you, or entertains you. Sending this to news.yc or anywhere else where marketing is a hot topic might- barely- qualify, because of the meta discussion it generates. The described trick itself is just plain spam.
Guerrilla marketing is an unconventional way of promoting on a very low budget, by relying on time, energy and imagination instead of big marketing budgets.
I would say that the example is guerrilla marketing.
Hi. I'm going to stick this sticker on everything I see. You, by default, will see the stickers. I will now call myself a guerrilla marketing guru. Pay me on the way out, but not before I stick this sticker on you.