Difference between using -san and -shi


I was at an event with high ranking Japanese personal, heads of a martial arts
organisation. People were asking for signatures on event passes, which had
their name written on it. As part of the signature, one gentleman was writing
the participants name:

ジョーさん

On the pass.

On mine however, he wrote:

ジョー 氏

I have read about the formality of using 氏, as used when you do not know or
have never met the person, however we have met many times, both training
together and meals, parties etc. I have great respect for him, and he knows me
by name, so I was wondering if there is anything else about the use of 氏 in
this case I can learn.




There is no such rule that "氏 is used when you have never met the person".
Where did you learn such a rule?

氏 does look relatively more formal, dignified or respectful, but at the same
time, less friendly. Still, さん and 氏 are both natural options here. If you are
getting an autograph from a young adorable
[idol](https://en.wikipedia.org/wiki/Japanese_idol), さん would be more usual.
However, it is not unnatural at all if a great person in the field of martial
arts used 氏 on his autograph. From what I can see, I doubt there is a special
implication here.

