They're popular in London too. The scam seems to be that if tourists don't arrange the price beforehand, it'll be arbitrarily inflated - they don't run a meter like a licensed taxi.
Always ask for a quote. That means every ride, not every visit to that city. And confirm what methods of payment they can take before you get in. If they're evasive or you get a bad vibe, don't get in.
If you decide to change your destination, make sure you get an updated quote first, for your sake and the driver's.
As a pedicabber of five years this is solid advice. Negotiate before you depart. I always made it a point to get buy-in from my passengers before we took off. Nobody wants to be surprised.
What many people don't understand is that pedicabs are independent contractors in many cities. We have full autonomy to charge as we see fit. Sometimes pedicabbers will gouge and sometimes it means the passenger will be surprised by an otherwise reasonable fee.
