Generally, three wheelers are more stable cornering if they are two in front and one in back.
The design is based on motor scooters. I know the Indian versions from 20 years ago had a lot of shared components, like the entire front fork, handlebars, engine, etc. The only thing different was the body work and the rear axle.
I saw a guy on a recumbent bike with 2 in the front, one in the back. He was sitting in a left turn lane directly across the intersection from me. The whole rig was very low to the ground. Moments later, a big F250 pulled up behind him in the same left turn lane. I expect he'll get squashed one day if he doesn't do something like adding a fiberglass mast with a flag so people can see him more easily.
While this may be so, the tuk tuk has been designed for stability. The USA version handels very well remaining tight on the road. It is even able to pull RV’s with ease and safety. The Tuk Tuk has been desinged exceeding DOT requirements.