it would be sensible to require a reason for refusing to do business with someone. Normally it wouldn't be but if you are a repeat offender it seems a sensible requirement
certainly, you can write anything on the form. Any reason is not without? I do doubt you can refuse one foo for being fooish but not the other. Now multiply by 10 000 and pretend you are explaining it to the judge in a context where you've been convicted multiple times.