Oh, I know.. Fell for it once in Thailand.. It was chucking it down with rain and I was in some backend part of Bangkok. Off the beaten track and without much choice.. I usually pop my head in and ask for the meter, if he says no, the door closes and I take my business to another driver..
Funny thing is on my last few days I am always happy to tip everyone loads as I am usually happy to spend the rest of my native cash on the country I am in. So it is a little funny to me when I give a nice tip to a waitress or taxi driver when I am due to leave, knowing that some mean person earlier that day lost out on more money than he hoped to make just for the sake of turning off the meter
Classic example was a taxi driver in Bangkok who demanded 400 baht for the ride from the hotel to the airport. The price was actually about 400 if he had his meter on (with road tolls) and I was planning a big tip (I had 700 baht lined up to give him). But because he was too ignorant, I took him up on his offer and paid him 400 baht. The cleaning lady at the fast food place in the airport got the 300 baht left over...