On a similar note - when i first came to Guangzhou, i used to use the subway pretty often. Whenever a seat became free i would sit down immediately whilst my PA at the time would hover above the other free seat for a minute of two before sitting down. I didn't immediately ask her why she did this - but i started noticing that a lot of other people were doing it aswell on the subway - especially women.

I asked her later and she said because you could catch piles or some other disease if you sat down immediately and 'warned' me to wait a minute before sitting down!!

Now i understand not wanting to put your behind on a public toilet completely....but i thought this was a bit funny...