Toddler Behavior Question

It's probably for the same reason they burst into tears when they first start visiting Santa Claus at the mall - they suddenly realize the adult talking to them isn't Mom or Dad, they didn't expect it and the surprise caught up with them and overwhelmed them a few minutes later.

I've seen this happen at the grocery store too.
A toddler goes to grab Mom's leg while waiting in the checkout line and got the wrong person.
Suddenly the kid looks up and suddenly realizes it's NOT MOM!
Waahhh!

At Costco we always kept our son sitting in the cart just to keep him safe.
Not because he would wander but because some people have really filled up carts, and they'd have a hard time seeing a small kid.
Small kid not paying attention + shoppers not paying attention (many are on phones) = run over toes or bumped kid.

Because she is 2 and got caught off guard. She scared herself.

I'd guess that 'being startled' by the experience just caught up with her a few minutes later. Kind of like, if an adult has a near-miss with another car or something - afterwards is when you start shaking...

Typical for this age to have a delayed reaction. I've seen kids this age fall down and pop back up and only burst into tears after an adult said, "You're OK!" Very young children often don't know to feel scared by a situation until adults try to reassure them or ask if they're hurt. I don't think this is about a kid crying at being corrected for being "wrong." It's just delayed shock at the bump and normal reaction to the sudden realization that she might have been in a bad situation that, at age two she didn't recognize for herself.

Please consider keeping her in the cart in places like Costco. I recently saw a toddler knocked over onto her backside (not hurt, fortunately) in a grocery store by a full cart and I think the person pushing had her eyes focused up on the shelves, not in the aisle. That's just where people are looking when they shop. Small kids are far shorter than the top of that filled-up cart, too, and hard to see even if you're not looking at the shelves.

Ellie,

Delayed response. It finally "hit" her what happened.

Just like after something happens, a near miss car accident...or after an accident - all is calm - once everyone is taken care of? People lose it.

Taking a child out of the situation helps. Reminding her that she's okay and no one was hurt, another way of dealing with it.

My friends daughter always cried when she was corrected. She is 12 now and still gets a horrified look on her face when you correct her.