Their security seems to me to be more complex than many celebrities. Princess Anne was almost kidnapped and her bodyguard was killed. I have read of plots to snatch Prince George. They ran into a bit of problem in one of the countries Meghan and Harry visited - was it Fiji? and security had to whisk her away as the crowds became somewhat out of control. I can see it being sustainable for a time but much more challenging for longer - especially when their whereabouts become known. I would assume the security arrangements for the royals while in England have been carefully worked out over decades by very experienced people. I was at a meals-on-wheels event for the stampede a few years back when Stephen Harper was prime minister and Mrs. Harper was there. She appeared to have one security person with her who stayed back and was very discreet as she mingled with the people. I just am not sure Canada really does that kind of intense, longer term, security. Don't know.