When a friend of mine was a conductor for London Northern/MTL London
Northern at HT in the late 90s, he said it seemed half the 30/40-plus
male population of Camden was travelling on Freedom passes, allegedly
for being being HIV+. At that time the condition was deemed to lead to
death within around 10 years, so simply being diagonised HIV+ warranted
being issued a Freedom Pass, regardless of whether the person had
developed full-blown Aids or ever would do.

I would assume any stolen Freedom passes would be used on the
Underground, where there is next to no chance of any ID card inspection.