As quoted by Anupindi:

"I was given a pair of trousers and the offer to find and make myself comfortable in any seat that I wanted in the rather empty coach cabin. I was told by the attendant that I would get a voucher by the end of the flight."

You can already see that the flight was not full and that you have been given an alternate seat. Had the flight been packed to the brim and that no other seat was available then, maybe you could have demanded to be upgraded. But still incidents like this do happen and even if it may have been foul smelling, you were not physically harmed by the substance.

True, maybe the staff should have been a bit more sympathetic but they felt that it was a simple matter.

I remembered years ago, I read a story about a flight from London to Johannesburg. It was a full flight and upon boarding, a South African woman made a comment that she refused to be seated next to a er...dark skinned man. Cabin attendants came around and advised her that the flight was full except for a few seats in First Class and that she'd have to sit down or else. She made a scene. The poor guy next to her was embarassed. In the end, the Purser came round. Asked the man to get up and then asked the woman to sit down. He then upgraded him to First Class!