If the fan forums were any indication, many fans said they wouldn’t boo Moochelle but would either turn their backs on her or leave the stands. Could be that’s what they did. Although if you notice - they announce the veteran and his family first to some cheering and THEN mention Moochelle - I guess they thought no one would notice when her name was mentioned.
And yep - you’re correct. The call to start engines is the equivalent of “Play Ball!” in auto racing - it’s met with wild cheering under normal circumstances.
I feel bad for the vet and fam but I’m sure they understand. I’m sure they had a great day anyway.