I also have an Ali story, actually two part, but only part of it pertains to this thread. Many, many years ago at a Tri-Star show in Houston I was set up, and Ali among all of the biggest names in all genre's of sports was signing. First part of the story I walk into the restroom and could not figure out why it was so quiet(this was pre 2000 and the show was packed), I look next to me and I am side by side with Ali. I walk out and his security detail are freaked out how I am in the room when it was supposed to be closed and Ali only. It had a double entrance and I happened to come it at the exact time they shut it down. So long story short I pee'd next to Muhammad Ali. Now for the real point of this post, there were probably 5-6 HOFers from various sports signing on the main stage all at one time, Bobby announced that Muhammad Ali would be taking the stage to sign, you could have heard a pin drop and the most impressive show of respect occured, Joe Namath who was signing, abruptly stopped his signing, stood up and led the crown in a standing ovation for Ali.

Another signing story, a bad signing
 

Although I don't collect autographs( the only one's I used to were Maris and Nellie Fox, no idea why), I used to do a lot of shows. One of the worst signing reactions I observed was at a small local show where a lot of Negro leaguers were signing(I think Dennis Biddle organized them), included many stars of the 1940 and 1950's. Also signing were a few ex MLer's mostly HOFers. So they announce the arrival of the Negro leaguers, they walk in a nice procession, the dealers and crowd all stands, claps and gives them their due. Gibson is seated at a table signing, does not get up, never even looks up, many of the honored Negro league signers were less than impressed and declared without them, he would not be setting where he was signing for much more than they. I believe they were signing for free, but paid by the promoter, where as Gibson was getting carte blanche, first class accommodations and getting paid to sign.

I am presuming you are referring to Bob Gibson?

yes, Bob Gibson.

Bob Gibson was prickish when I met him, but he did signed as I wanted.

Bob Gibson
 

Around 2004 at a Cardinals spring training game in Jupiter, FL., Bob Gibson came over to some fans along the right field foul line to sign some autographs. I was second in line and had his '59 Topps rookie card ready. When he saw it, he flat out refused to sign it. His reasoning when I asked him was 'that's card show stuff' (He wanted the $$). Was it that big of a deal?

he told me, "I don't write books"

I remember when I was a kid Bob Gibson came to White Plains. It was the same show as Tom Seaver. Seaver, like I said, invited me behind the table, asked me my name and took a nice photo with me. Even though Bob gave me a pretty solid autograph, the photo of me and Bob is of me standing on one side of the table while Bob stares at the floor.

I was never into having a photo taken with a player. All I want is a personalized autographed photo, and then I am out of there!

No longer into it now but I was only 10 or 11 years old at the time. Plus this was before camera phones, so documenting things had a little more meaning behind them.