There is a political conflicts in Thailand right now. The demonstrators try to overthrow the elected government because they think the government is corrupted and undignified. The protests have been going on for quite awhile but the protesters say the government should come to an end soon so they started the big demonstration on Monday. In fact, they already took over the parliament and other official buildings.
Anyway, I think that the Crown Prince couple won't be bothered by that at all. The protests are at only certain government official buildings which can easily be avoided. I hope they have a good time in Thailand. The weather is nice and warm!