Tram's, Theft and Moral Obligation

On my way home from employment today I boarded the Luas from Abbey Street, it was - as is to be expected at rush hour - crammed. I feel, at this juncture it is necessary for me to digress somewhat. I am paranoid, and I mean not "they are after me" paranoid more "that man wants to rob me" paranoid. I suppose, cautious to the nth degree would be a better description. I suspect the worst because the worst will normally happen.

Anyway, back on the tram - to the immediate right of me sat on the disabled chairs (chairs for use of disabled people and not chairs with some physical handicap) sat a man. He had obviously expensive headphones on, following the wires downwards I could see that they were attached to an iPod. Again, an expensive luxery item.

Within the crowd two men, roughly mid twenties, were walking down the crowded aisle. Thin men with tattoos and short hair.

At Smithfield a couple pushing a pram embarked. They stood near the entrance doors effectively blocking it off. The Luas started up again.

The man with the iPod sat watching a video, the two tattooed were walking further down the aisle. The new parents cooed at the child. My eyes flitted from person to person and from my feet to my hands. Sometimes they shake. My own iPod was playing something non-descript. My mind began to wander when the entire tram burst in to noise and bustling, awkward violence.

The two lads had grabbed the man's iPod as soon as the tram stopped. He was clinging on the one of their coats screaming "give me my phone, give me my phone". The one who had grabbed it was desperately trying to break free and flee through the slowly closing doors. His mate stood as a barrier between the man and the thief. As they were running for the doors the clattered into the pram, the man still shouting and trying to hold on. Unfortunately he was unsuccessful and the two lads got away - ironically, running towards the courts in a bid to escape. About four minutes after the robbed man got off the tram the inspectors came and asked for my ticket. A woman started to describe what happened and I briefly added some supplementary detail. Such as they were young, one had distinctive tattoos. Bullets on his hands. But I got off at my stop and left for home.

This has gotten me thinking. Is there anything else I should or, indeed, could have done? I don't think I could have made it across the people to stop the men - nor could I have done anything of any great value if I did. I could have called Garda Confidential and gave a description but they will not recover the phone nor would they be able to get the men. The phone is probably covered by insurance on the contract. One could argue that by displaying such an expensive item so brazenly is asking for trouble. That is a controversial and dispassionate point, but a point none-the-less. I have mine close to my body and difficult to steal. Also, they do have frequent warnings about pickpockets on the tram system. But that evades the point that someone just minding his own business was violated and stole from. And I, along with others, didn't and to an extent - couldn't - do anything. I wish I could have stopped them but that would only have preceded with me getting a sound beating. Not something that I am particularly keen on getting.
Am I under a moral obligation to say or do something? What, realistically, could I have done?

This just reminds me of the lines by Martin Niemoeller - who was a Catholic priest during Nazi regime:

"First they came for the Communists, but I was not a Communist so I did not speak out. Then they came for the Socialists and the Trade Unionists, but I was neither, so I did not speak out. Then they came for the Jews, but I was not a Jew so I did not speak out. And when they came for me, there was no one left to speak out for me.”