To be honest her beef should be with the DSP not Iarnród Éireann. They had asked for the pass to be detained for whatever reason (defacement, temporary suspension of claim etc) not the ticket inspector.
To the people reading this with the paper passes. If they become old and tatty go to your local Garda station with this form
http://www.welfare.ie/en/pdf/ft27.pdf get it filled out and send it to
Free Travel Section
Social Welfare Services
College Road
Sligo
If your pass is in such a bad condition that it is unreadable DO NOT WRITE ON IT get it replaced. Also always carry your social services card with you too.