UC and self-employment

How does UC deal with self-employed earnings that are not from ‘gainful self-employment

Client works part time and earns above threshold so no WRR.  She is considering selling things she makes at craft fairs,  on facebook etc.  It is a hobby that she would like to make some money from but in practice profit will be minimal. Will not be registering as self-employed with HMRC as earnings will be below £1000.

She is clearly not in gainful self-employment and even if she was would not have MIF imposed for a year.  My questions are: Does she have to report she is self-employed and report any profit monthly? i.e. do the rules around gainful self-employment relate only conditionality or do they apply to income.  Or would she need to report the income in a different way?

At the end of the year I cannot see a MIF would be applied (as not in gainful SE) but wonder if anything could potentially change?