[*mazedsalv**]

Think about it. Sara's mum wants her daughter to go far and get on with the others and try not to get nominated, so she nominated:

Scott, who is a floater and Becky who is now an insider, but is probably not even liked by the insiders much. By her Mum not going with an definite outsider nom or insider nom, it makes her safe for the next nomination round (if there is one). Had her Mum went for insiders, they would target her next week, and same with the outsiders. That way I think Sara's Mum just saved her daughter by not exposing what team she actually is in.