If a unit is sent out on loan for review, rather than being given to the recipient, $100 is not an unreasonable nominal fee. There should be no tax to pay on it.
The modulated output sounded much more like a square wave. Very harsh at the lower frequencies with lots of overtones. Maybe it was fooling the AGC and clipping the input gain.
One thing that still amazes me when people un-box stuff, they try to lift a comparatively heavy item out of a cardboard box. This means you have to struggle clamp the box between your feet or get someone to hold it, wobble the item around and risk dropping it or falling over. Far easier to fold the flaps back, rotate the package onto the side, then onto what was the top. Lift the cardboard box off. Done. Obviously don't be a twonk and do this on a floor strewn with gravel and an unprotected item (very rare nowadays).