This reply is based on my experience as a parent of an Autistic young man quite capable of independent travel
For him rail travel is a normal but sometimes stressful in unusual ways.
As with all of us situations and circumstances can gang up on us to make travel that much more stressful and a reaction could be 'unusual'.
Before a situation jumps from being an 'unusual' problem to a "the duty of care" Police issue, can we all be a bit careful.
Please, if rail staff are ever worried about dealing with these issues and feel they will be blamed, please protect yourself by recording the events on your phone. No employer, court or relative will take action if you have tried your best.
Staff and public nowadays are much more aware of such conditions as Autism and its often because of real situations they have dealt with and usually all that is needed is calm.
Often another member of staff or a member of public can be very helpful -not interference- helpful.
In our situation I encourage him to show his disability bus pass (not entitled to a rail one) and a card which asks the " Railway Staff" to patient and understanding and to contact me. Never needed, but it is a reassurance. EMT (Sheffield) are very good at providing an appropriate level of support and advice-thanks. They provided a link to a printable card scheme. I know other TOCs have similar schemes.
He cannot lie but he can be bamboozled.
Unfortunately the worst thing to happen is when the "massed bands of the revenue protection teams" descend. Can we please have barriers in Sheffield?
Ooops forgot about the Manchester Piccadilly (bridge above) platform 13 and 14 revenue people- unbelievable. Thank you to the two off duty "Virgin" staff for sorting them out.
Don't let this detract from the level kindness, help and offers of support from rail staff, which has become the norm.