It depends on the TA.
My SIL is a TA and starts an extra half an hour before her paid time to prepare their classroom every morning - unpaid, she has several children with SEN and can’t do it when the children arrive.
She also covers break time playground cover 3 times a week- unpaid as they don’t have enough staff.
She has to deal with any children who have had a toileting accident during lunchtime- unpaid, not enough lunchtime supervisors.
She has to complete any after school training- unpaid, no money for overtime.
She has to go on school residentials, - unpaid , ( they at least do this on a rota).
She works an extra 15 minutes a day, unpaid- talking to parents, tidying up.
She has to cover the teacher if the teacher has to go to a meeting- unpaid.
She covers the teacher’s PPA for a measly £2.50 an hour.
If they go on a school trip and they are late back - unpaid.
She does this every week and isn’t the only one where she works that does it. There is no money for overtime and apparently they are over staffed so can’t get an extra staff employed.
She would be mightily pissed off if they docked her a day’s pay for a special occasion. There should be some discretion because that school would fall apart if it wasn’t for the goodwill of staff keeping the school going. She gets paid minimum wage.
And yes, we tell her not to do it but that’s easier said than done when she sees children struggling.