What the....???

So, at the museum yesterday, Katie and Jack are playing quietly and very well-behaved with the musical instruments in the Clifford room. I was letting them play because a.) that's what the museum is for, b.) they rarely play that quietly, and c.) no one was waiting for a turn. Out of the blue, a woman walks up to Jack, snatches the mallet he is using, and hands it to her child. I stood there in absolutely shock for close to ten seconds. I mean, really??? She grabbed a mallet out of Jack's hand while he was using it! He hadn't set it down. He wasn't holding it and not using it. He hadn't even been sitting there all that long using it. Plus, she and her child were not standing there waiting for a turn. She just snatched this mallet out of Jack's hand. I truly and honestly wish that I had recovered quickly enough to gently take it back and tell her than when my son was finished, her child could most certainly have a turn but I was just so floored by the fact that a full grown woman (maybe early forties) would walk up to a toddler and snatch something out of his hand. At least I didn't give in to my original desire to smack her hard in the head and start cursing at her and calling her names!! I didn't think that would teach my kids too many good things besides a colorful array of curse words.