How should Effects handle Nodes with 0 size?

While investigating RT-2280, an interesting interaction between Effects and empty Groups was discovered. Ordinarily, the bounds for an empty Group is a rect of 0-size. However, using certain Effects such as blur or shadow can causes an increase in bounds. This leads to a strange situation w/ the painting code, where we have a non-zero dirty region, yet nothing to actually paint.

Should Effect bounds and other calculations be performed if there isn't going to be anything to render in the end? Is there a possible optimization for Effects applied to Nodes/Groups of 0-size, such that they don't have their bounds expanded?

Or perhaps there is a reason the current behavior is necessary?