I wouldn't buy a car, even new, without a test drive. Why would it be different for an airplane?
In an airplane though, I'd expect a test ride -- as pax, not as PIC.
That said, as I recall I bought my current airplane (C180) without a ride first-
because I knew the owner & a number of his flying buddies,
and was somewhat familiar with the airplane & comfortable that it didn't have any big issues.
Pretty good info here.
This weekend we completed a purchase of a cheap set of wheels, a 7 ECA. I have known about the plane for a while, life changed a couple weeks ago and we need to travel to Juneau lots this winter- airline tickets are $150-$170 each way, so having cheap wheels is worth it. Maule still in recover.
I called the mechanics that have done the last couple annuals, guys I know and trust, and got good words from them. Talked to the owner through texts as he was working out of town, he promised to hold it for a pre-buy. Took a week to get the pre-buy done, (I was only concerned with wing spars and engine). Got word that the plane was good, sent the check the next day.
I did not fly the plane, nor did I run it. BUT mechanics that I trust, and have done major work for me, knew and flew the plane recently. And the price was right.
A number of years ago I traveled to Anchorage area to purchase a PA-12. The mechanic had purchased it as a wreck, and put it back together. I wanted to do a compression test, check the screen and do a test flight. Upon my arrival the owner, a mechanic, said he had already pulled and cleaned the screen and told me it was clean; first flag, as I had known an inflight engine failure had caused the crash. I needed to see the screen myself or by a mechanic paid by ME.
I decided to hold off on the compression test and panel pulling until I got a flight in it. Took all of about 20 minutes to do a stall or two, couple turns, and have him put it strait and level and let go of the controls, then come back to the airport. The owner did the flying with me in the back seat.
When the owner pulled the power back for landing the engine quit. The owner said it did that sometimes.
I had $1,000 in travel already to see this plane, with over a weeks notice to the owner, and A&P. The plane had a history of inflight engine failure, and the owner/mechanic was flying it with the engine commonly failing during low power settings.
I walked away without any concern for reimbursement for the flight or effort the owner had gone to. The plane was not airworthy as advertised, and honestly not safe.
Getting even a test ride on unknown aircraft is well worth your time. But, as long as the person flying it will do what you ask within reason- hands off strait and level, stalls and such, being a passenger will provide you with the information you need to evaluate the plane.
On a cub, I would expect to take a serious buyer for a flight, I might let them handle the controls once above 500 feet, but I would be landing it.