You'd lose that bet I'm afraid.

While there haven't been any solar sails used for propulsion the effect has been measured in the lab (way back in 1901). In fact it's something that has to be taken into account in existing interplanetary flights. The light pressure on solar panels, etc. is enough to have a measurable effect.

Crook's radiometer isn't an example of light pressure. This has been known since 1879 (see this comprehensive explanation for more info). I am more than mildly surprised that Gold is in ignorance of this since I was told about this in school!