As in most things it appears to be a bell curve... at one end, if NObody knows who you are you could have a minor cardio- or cerebro- (or with three heads, a cerbero-, but that's uncommon) vascular accident which ould rapidly turn major for lack of attention.  Or, some criminal predator could break in, and your safety level would be less than if someone "outside" were paying just a little attention to your life.

At the other end, if EVERYbody knows who you are, you're pretty safe in the medical emergency category but not so much concerning criminal predators, and the US Secret Service (inter alia) agrees with me there.

So big surprise, Moderation may turn out to be the Golden Mean, if that's not too pleonasmic.  "To a point" the more people know who you are the safer you are.  Past that... there is a downturn... but the vast majority of people sit nicely on or near the peak of that bell curve.

The breaking point at the low end is of course:  zer0 people know who you are.  Your safety begins to soar upward with merely one associate and even more so with two.  The low end of the bell curve is steep—how about the high end, where's the falloff point...?

A long guess is "150 people" which is based upon simian research.  There is apparently a limit on how many people a primate can be actively associated with and fully aware of on an ongoing basis; it's called the Monkey-Sphere and for humans it's 150...as usual, I'm not making this up...

So.  Say 200 people know you.  You can only be active with 150 of them, leaving 50 people knowing who you are and also knowing full well you just plain don't care about them.  The rational response to this state of affairs is "So what?" stemming from the at least subconscious realisation that nobody can care about everybody individually, but only in the abstract.

Only someone seriously deranged would ever take the slightest offense. Out of those, very very few will have the bad wiring it takes to bring them to the point of violence against someone in their own Monkey-Sphere with such a trivial cause.

From common sense interpolation of the odds it becomes clear that you can probably have as many as 1000 people knowing who you are before your personal safety level realistically budges from absolute peak.  Maybe more.  I'm not sure what the threshold is for "celebrity" status, as out of any given 100 celebs in the news on any given day I only know 20 of them...who makes up these rules anyway?  Ever wonder that?  Whatever. It's pretty clear that your personal safety level falls off pretty dang gently with the addition of each 1000 people knowing who you are.

In view of all this fancifully extrapolated insight my personal standard is (now), when I get 10,000 instances of fan mail, both snail and e-, I'll assume only 1% of fans ever write, so I'm up to a million fans, 999,850 of whom could conceivably hold an irrational grudge, and it's time to hire a bodyguard.  A good one.  Because I can beat up most bodyguards I've seen.

Not that I ever would.  That thing on July 17, 2006, well it wasn't me; I wasn't even there, and I wish they'd leave me alone about it, and that definitely means YOU, Benjamin H. Grumbles, Assistant administrator, Office of Water, EPA.  Cripes!

—Ron Copis