But there are limits for good reason: if they broke parole in order to volunteer at a food bank or give blood, these are not valid motivations in the eyes of the law. Emergencies are, by common agreement, different than most other circumstances.
That determination can be made by the judge so that the jury doesn't hear emotional arguments about how important the work at the food bank is and potentially be swayed. It's the same as the judge deciding what evidence is admissible - we don't show the jury absolutely everything because some is likely to lead them to return a verdict we know, through experience and careful consideration, to be incorrect.