Good idea for the thread. Well, Singapore sure got ripped-off in it's purchase of Shin corp, so maybe Thaksin will get it eventually - what goes around, comes around.
Here in the Sitiawan, Manjung, Lumut, Pankor area I haven't been over-charged vs locals as there's not really anything to visit.
The tourist shops on Pangkor Island seem to have an "equal opportunistic policy" as they pretty much treat every tourist the same. In Lumut I've been overcharged a couple of times but after saying, "I think you've made a mistake" the price gets back to normal.
Some traders see a foreigner and their faces light up. They think that we're dumb and that they'll make a killing. The nice thing about Malaysia is that it's all a bit too obvious. You can see it coming miles away.
I agree with you that Thailand makes a distinction between Thais and fallangs. It's the familiar, "you're not Thai" approach which is annoying but fair enough.
What about China? When I was last there I felt like a commodity. Part of the annual "crop" - plant, water, reap, and leave out to dry. My travelling companion spoke Mandarin and taught me to say, "I don't have enough money" followed by "no really, my whole family is destitute and I have big debts." I had the phonetic English for these phrases written on my hand. The touts fell apart when they heard this stuff.
Win some, lose some.
regards, Scott