Immigration officers counting cash at BKK... imagine how much time that would add to the non-priority lanes... and government employees counting cash anywhere doesn't exactly look good.

My uncle likes to tell this story about how he was waiting for an hour in a Thai immigration queue in the 1970s while some people were getting through in a few minutes, until he apparently realized that they were slipping some cash in with their passports, so he asked for his passport back and did the same, then was let through straight away. Don't know how much he is exaggerating what really happened.