entry visa. When we called Embassy, we were told that EU and Australians, US no need visas, so we were happy to hear that BUT when we arrived we found out that we have too! so had to pay 60usd for adults and 17usd for kid. Of course they tried to charge for kid 60usd, then I asked WHY and was told - ok, pay 30usd, when on the window was written 17usd, so had to change money to ryals and pay in local as it was easier for them to count!
VISA card - mostly not accepted, even tough we were told that hotel is ok to pay by credit card, on the end we found that is not! they only accept Amex and Mastercard.
Yes, I guess 80 percent of my tourist traps are about taxi drivers, I am sorry(well I am not really) but this is usually the problem I meet around.
Reguarding Sanaa problem is not their honesty, ofcourse you have to bargain with old taxis which have not taximeter, but once done, they respect the price.
Problem is they often have no idea of where you are going and they ofcourse forget to tell you about it and will stop other car drivers in the middle of the traffic to ask them if they have an idea of where you want to go, and this wandering can be very long.
Unique Suggestions: At least make sure that someone writes for you in arabic the name of the place where you want to go that makes life of the driver easier.
Fun Alternatives: Try to ask for some known places around your destination, for example if there is a popular hotel or an important mosque so the driver has at least an idea of the area where you are directed to.