Funny story, I had a similar story , but I was the one who had the wrong person.We were at IOA, I always hold my wifes hand when we walk and
she at stopped for some reason , I waited ...then I reached out and took her hand and started to walk. Well she jerked her hand back quickley I turned around and there was a woman looking at me like I was a nut case. I could fell my face turning red, I said sorry, wrong girl . Went on to find my wife who
was looking at clouds or somthing
Both stories were pretty funny. I've talked to strangers who somehow ended up standing next to me where I thought a family member was, but luckily I've never grabbed one... 
A good reminder for crowded locations: Always look before you grab.
But that takes all the fun out of it!
If you used "bottom", "hiney", or " gluteus maximus" instead, it'd be PG-rated. 
Adding my story to the mix...
When my daughter was small, I once watched her run up to a strange man, grab his hand and start heading off with him. The man looked down her and said, "Hello...?" The look of sheer horror on my girl's face when she realized she was not, in fact, holding her daddy's hand was hysterical. She quickly found her REAL Daddy and burst into tears. The poor man couldn't stop apologizing, even though none of it was his fault!
Adding my story to the mix...
When my daughter was small, I once watched her run up to a strange man, grab his hand and start heading off with him. The man looked down her and said, "Hello...?" The look of sheer horror on my girl's face when she realized she was not, in fact, holding her daddy's hand was hysterical. She quickly found her REAL Daddy and burst into tears. The poor man couldn't stop apologizing, even though none of it was his fault!
Typical Europeans.
My husband is from Scotland and he is the same way.
When my son was about 3yrs old he had a habit of holding onto my leg when we were in line for rides at any parks we went to . We were at Kings island waiting in line for I think was some sort of kiddy coaster ride and I was of course holding onto one of his hands. I had turned away for a moment , then I looked down at him and he has his other hand up some strange mans' shorts (on the outside leg area...only ) I apologized to the man (who had a look of shock on his face) numerous times. Kids... turn your head for a moment and you never know whats gonna happen This happened about 13 years ago 
