There's a little more to this than meets the eye.

There are stories about tuk-tuk passengers being drugged and mugged, so tourists are encouraged to take the safer government licensed taxis (cars) rather than Tuk Tuks. In addition to that, foreigners can be seen by some Thais as immoral and unwanted visitors. The phrase Farang Kii Nok indicates you are dirty white and have fallen out of the sky, quite often applied to backpackers.
Also, remember that many foreign men go to Thailand for reasons of child abuse, this is quite open in Bangkok. So dislike of these sort of people is very understandable to say the least.

Anyway, that is why some tuk-tuk drivers have signs like this, mainly to indicate they will happily take money off you and not kill you or make any moral judgements on your weird ex-pat lifestyle.

It's mainly just a sales thing. You will not feel the love off a Tuk Tuk driver, and if you do ... you will wish you hadn't!

I bet this would go down great at an Airport.

re: the widest generation gap .
I was reminded of this article - "Say Everything" about youth today
http://nymag.com/news/features/27341/

http://www.snopes.com/photos/advertisements/vwpolo.asp

the link to the telegraph is just the word 'link', not an actual link.

surely ham dressed as mutton?

it's a pig that looks like a sheep

I believe the monkey fist was the knot aimed at James Bond's nether regions in the 'Casino Royale' torture sequence.

my personal favourite line :
"It is thought he has made in the region of 30 citizen arrests over the years.He has clung to the bonnet of a car to try to stop a hit-and-run driver escaping and has also chased gangs of youths trying to steal cars near his home."

conjures up a marvelous mental image of the middle-aged webslinger

I own one, like Matt says, it's for holding your book open with one hand.

I bought it and used it about once, quite unpleasant in use. I realised I was perfectly capable of reading one handed without an uncomfortable lump of plastic on my thumb.

there are some images of the real guy in action here
http://www.ktvz.com/Global/story.asp?S=6759982

don't miss the video

http://www.nature.com/news/2007/070702/multimedia/070702-7.mov