Is it known whether any of the passengers had personal bodyguards? Many of the first class passengers were of considerable wealth (Astor, anyone?) so I have to wonder whether any protection travelled along with them on the ship.
I would imagine valets did almost everything but comb a royal's hair, and if their superior was in any kind of danger I would think the valets themselves would allow their valet duties to go beyond. It seems like only those with considerable wealth are the ones most prone to danger, but then again there are many millionaires who roam around without protection. Could it be only those who amass a certain amount of publicity, are the ones most vulnerable to danger? Don't know.
If any passenger needed protection it would have been the aid to Theodore Roosevelt -- Mr. Archibald Willingham Butt, but I do not recall reading about any such protection.
I'm not aware of anyone who served as a bodygaurd but then this isn't the sort of thing that any of the well to do would be all that keen to advertise.
One thing to bear in mind is that the attitudes towards personal weapons were very different from what they are now and it's a documented fact that some of the passengers and crew were packing guns or had them available. One of the officers...Lowe if I recall correctly...had his Browning automatic and fired it to discourage a rush on his boat as it was being lowered. Also, Michel Navratil Sr. had a loaded revolver on his person when his body was recovered, and nobody was particularly upset about it. it just wasn't regarded as a big deal.
It's not much of a stretch to suppose that if some of the wealthier passengers thought they needed an equalizer that they would bring Smith and Wesson or Colonel Colt along with them on the trip. Since they wouldn't be flashing it around, nobody would have been the wiser.
Norman C. Chambers, according to Lord, pocketed a revolver. I assume he was the man who told Karl Behr in the lifeboat that, if things got desperate, Behr could use the gun on himself and his fiance after the man and his wife were done with it.
And according to Judith Geller, Charlotte Cardeza used to attend the opera with bodyguards to protect the priceless jewels she was wearing.