You both are correct.

I'd desirable to have a block of wood between the stand and the vehicle so that the contact point is larger. A typical jack stand such as the one Dave is using will cause localized damage to the sheet metal. Not a big issue, but, it's a point where rust will begin, if given half a chance.

However, wood on top of such a stand is dangerous. The platform on top of the stand is insufficient to support a block of wood and it's quite easy to split it in half.

The final solution involves finding a jackstand with a nearly flat top. I found a set of aluminum stands with just a slight depression and I had the machinist turn that flat. So, I've got a platform of about 2" x 2" that will safely support a 2" x 4" and won't run the risk of splitting it in half.

These stands are available at various outlets and I like them quite a bit.