Self employed

My (retired) spouse babysits on rare occasions at the local gym for people working out. This is not often, only on occasion.

 

Last year, she made less than $600. This surely can't be a business, can it?

 

The gym gave her a 1099-MISC with the amount in box 7, so TurboTax is forcing her to file as self-employed - but this is not a business!

 

What can we do?