Yes bob. My ds' 1:1 sat ds at the back of the classroom with her and the disruptive kids so she coukd do a job lot for the teacher.
DS actually needed to be at the front of the class undistracted by bobbing heads with a TA having prepped, prompted behaviour and rewarded him for developing his listening and behaviour skills,
Instead he was at the back silently stimming and being provoked by mischievous children that his TA was also 'looking after'.
I don't think as a TA you can challenge this very easily though.