Of course, Bill Gates has bodyguards. He is (as of February 2018) the second wealthiest person alive. Lots of people probably want that money – at any cost.
Everything changed after an incident in Feb 1998, when Bill was attacked by a team of men in Brussels, Belgium. Fortunately, they only attacked him with cream pies. Some kind of ignorant misguided attempt to become famous for being a dick.
It was obvious to Bill that similar stupidity had killed John Lennon. I don’t think it had occurred to him that his fame had grown to such an extent that he would become a target.
Prior to that incident, Bill was really accessible, he travelled a lot by himself. After that, everything was immediately different. When Bill travelled, even to other Microsoft subsidiaries, he was always flanked by a security detail of at least 2 big guys, often many more.
The security in his office in Redmond was beefed up significantly too. Where previously any employee could wander into Bill’s office, in building 8, after hours. After, they built a new, extremely bomb-resistant building, all windows were inches thick. And moved Bill into it. Without an invitation, you couldn’t even get onto his floor. I know a few who tried. They were politely intercepted & put back in the lift. The corridor leading to Bills office was full of offices for his security people. Even if you sprinted you would never make it close to his office.
I can’t say how much this change was driven by Bill himself vs Microsoft Corporation insisting they needed their most valuable asset to be protected. Clearly, he had to sign-off on it. But doesn’t mean it was all his idea.
It is unlikely that this level of security protection would have decreased.