Billy Graham had men with him all the time. They'd get in an elevator first or enter a hotel room first, all to prevent any possible "gotcha" moments. All to prevent the slightest APPEARANCE of impropriety, let alone the actual thing.
Thanks - I was going to mention this too.
Our pastor has a similar policy; he has a male secretary, and will not travel alone with a woman (must be at least one other person if traveling with a woman).
Which all begs the question - why? Simple; our adversary is is always seeking someone to devour, and sexual sin is such an easy trap (meal).
“...make no provision for the flesh, to gratify its desires...”