Why/When did a statement of support become actual support re: the troops?

If someone has a bumper sticker that says, “I support my local Girl Scout Troupe,” one would assume that they assist in some volunteer capacity or at least buy the cookies. If the bumper sticker says, “I support my local police auxiliary,” the assumption is that the bearer has donated time or money. Even ”[Candidate] for President!” on a sticker generally means that the person has plans to vote for that person in the upcoming election. All of these are tangible forms of support that they have given to their cause, and the sticker simply announces to the world that they have done so.

However, in the case of “Support the Troops!”, why is the act of placing that yellow ribbon considered the actual support, as opposed to a statement that the person with that sticker (or lapel pin, etc.) actually supports the troops in some tangible way? Even if we rule out the fact that the message is imperative instead of declarative, it is widely considered true that this act of declaring support is equal to actual support, and there is no need to back it up with action.

In short, I’m curious as to how messages like this, which regularly make the rounds at places like Facebook, actually support the troops:

It’s time to show the world that more of us SUPPORT our Troops than not. If you support our Troops then please post this on your status and leave it there for one hour. And if you don’t stand behind our Troops, then please feel free to STAND IN FRONT OF THEM!!

Do any current troops, or any of the 131,000 homeless vets, feel supported by a Facebook status update or by a yellow ribbon sticker? Would they feel more supported if the status stayed up for more than an hour? And when did the message that you support the troops become the actual support, rather than more concrete forms of support such as victory gardens, rationing, and a top marginal tax rate of 90% as seen in the U.S. during WWII?