['I lost over £200 on public transport about 3 years ago!', "Oh no! That's a lot of money. Did you get any of it back?", 'No! I lost the lot! It was my own fault for being so silly and leaving my wallet out when unpacking my bag!']
Doesn't give anyone the right to steal it, tho'. I'm so sorry - how awful for you. I hope they had a horrible time when they tried to spend it!
I managed to lose a lot of money through leaving it on the train