[post_page_title]Look, but don’t touch[/post_page_title]
If you are not a royal then you are simply not allowed to touch one. The only people allowed to touch other royals are the royals themselves. There was a public outcry when American LeBron James was spotted touching Kate Middleton during a royal visit.
It was once believed the monarchs were appointed from Heaven so touching them was forbidden for mere mortals. That rule is largely followed today, even if not all people are aware of it.