Lauren, This is all too often
Lauren, This is all too often a story across the country. The Honda salespersons do not seem to be good understanding, or selling, the Clarity. There are many comments on the internet about test drives with a flat battery.
The truth is up to the EV range of the car, somewhere in the high 30's to low 50's depending on the ambient temperature, you can drive in 100% electric mode quite easily without tripping the engine. We drive for weeks at a time without the engine ever coming on. Then when we are on the highway taking an out of town trip we will switch into HV mode which is Hybrid Vehicle.
In HV mode the car switches between the engine running to add power to the battery + to the drive motor, and electric mode (EV). The engine will turn on and off without us noticing. Without looking at the dashboard display I can't perceive if the car is in EV mode or HV mode. However there are times when we do hear the engine.
It's important to know that the gas engine normally does not connect directly to the wheels (it does under certain circumstances). The gas engine's job is normally to supply electrical power to the electric motor that drives the wheels. So the speed at which the engine runs has no relationship to the speed of the car. The engine may run fast to both supply power to the drive motor and to recharge the battery. In some cases the engine will run fast and noisy. There are even times when the engine runs so fast we've deemed it "angry bees" mode. While a little disturbing this is normal, but rare. Our Clarity has over 17,000 miles and I've only heard the angry bees sound once which lasted a short time, like 5 minutes. Most of the time we never hear the gas engine either because the car is in full EV mode, or because Honda did such an amazing job of having the gas engine come on and off without being able to notice.
Many of us await the day Honda puts a Clarity like PHEV package into a CR-V or HR-V.
I'm sure you will be pleased if you get to demo a Clarity with a charged battery. Good luck with your decision. We love the car.