Jeff, while I almost always agree with you, this time I don't. Common sense is the reason. Every single detail in this urban legend is probably known to every foreign government. All of this information is easily attained from casual observation. Also, it isn't just the SS who knows this stuff. I, myself, spoke to a Marine who worked the White House and who told me one or two things. People love to gossip. No way to stop it.
Nonetheless...the Secret Serfvice details know that they must not give out such informtion. That President Bush makes a habit of, or commonly goes to certain aircraft to thank those crews is information, if it becomes known, that an enemy could exploit to significantly increase their ability to target the president in certain situations.