Excuse my ignorance but what is that? The traditional Islamic head wear?
Ah see, thank you.
Basically, Saudi Arabia is saying "we respect that you are not a follower of Islam and we like would rather ha ve you visit and respect your right to be who you are rather than insist you do something against your will or Faith.
Wise move by the Saudis (for once). As stated, probably a nod of respect to Trump and his wife. Melania is more than just First Lady, she seems like a fairly strong woman who isn't just defined by Trump, probably one of the reason Trump married her. Good for her.
I remember a number of years ago a co-worker of mine introduced me to his wife. He was Muslim and I said hello but didn't extend my hand to shake it. He actually thanked me for that as I knew it wasn't acceptable in Islam. I did so out of respect, and I am the type that figures, "it's no skin off of my back to respect his beliefs which I was aware of".
Now, I have my limits of course, so I just wouldn't place myself in a situation in which I have to be something I'm not.