(17 Aug 2014, 2:30 pm)Dan wrote It doesn't really inconvenience the operator at all, aside from the light mileage incurred from the depot to the nearest point to the depot for that service...
It inconveniences customers the most. As you say, these buses stink. Smelling sick makes me feel sick. It's these customers who are often paying for day, week, monthly and annual tickets who are having to endure an uncomfortable bus journey as a result of someone else - and if the bus has to be removed from service where another bus isn't available (as in the recent case which prompted this discussion), it inconveniences all those customers who are stood at a bus stop like a numpty waiting for a bus to show up.
Of course it inconveniences the operator (as well as the passenger) - that is why the penalty fare is put in force by taxi operators.
The vehicle has to be taken out of service, cleaned, disinfected etc - whilst a replacement vehicle is sourced and dropped into place (with potentially a replacement driver at the wheel - possibly starting a shift earlier than planned, leading to problems further into his/her shift once hours are up).
Then there is any associated admin to complete for lost mileage etc
The inconvenience for the operator is massive.