The system in Delhi is different from what I had been used to in Calcutta. Here the DTC buses are Government funded. Thus, there is no realistic incentive on the conductor's part to ensure that every passenger buys a ticket.
Today, a random survey occurred. A group of inspectors got on and started checking everyone's ticket. In this process one frail man, clothed in the grime of his economic disposition, tried to get off so as to avoid being caught without a ticket. He was consequently grabbed by the collar, brought right back into the bus and given a not-so-gentle warning about the consequences of such an act. In fact, by the looks of it, they "challaaned" him but I am unable to ascertain his fine.
That's how things happen in Delhi. The poor are made to feel even more insignificant by the treatment meted out to them by those in power. In this city, very honestly, money equals power. If not money then at least your position in society does. If people need you then you are powerful.
However, keeping my socialist emotions aside, I will now go back to telling you about buses in Delhi.
As I said, the bus conductor does not have an over-riding need to sell tickets. His salary will keep coming. He is a Government employee. He does not work on incentives.
I have been on state buses in Calcutta as well. I don't know if the conductor has a similar system of payment there but they do make a significantly larger effort to sell tickets. In Delhi the conductor will not budge from his seat. The passengers will have to buy the ticket from him as soon as they get on. Thus, during rush hours (office time) when a deluge of people get onto the bus, the ones who don't wait around the conductor to buy a ticket slink away and occupy whatever seats are left empty. So, you see the fallacy in the system. Not only do the ticket-buyers buy the tickets, they also lose out the empty seats to the non-buyers.
I am sorry, but this kind of a system only consolidates the Babudom that is prevalent in Government agencies. It's an ignominy for a passenger to wait around the conductor and buy a ticket. It is the conductor's job to walk around and make sure everyone buys tickets. This will also ensure that errant passengers stop taking chances and either buy a ticket or not try to avail a free service at all.
I have been to Bangalore and there too the conductor walks around the bus to sell tickets. This is the right way. It ensures revenue and also avoids ugly scuffles that I happened to be a spectator to today.