The Reflection peers ignore the provided clip and generate their full output in all cases.  This can result in extra unnecessary pixels being processed by the Reflection effect itself and by any effects that are being cascaded on top of it.

Note that since the Reflection effect operates in untransformed coordinates, the work done by the effect and the size of data it produces is not affected by a scaling transform.  The fact that it ignores the scale of the transform, though, could be considered a bug in its own right, but that bug can't easily be fixed until the reflection effect honors the clip or the system could run out of memory under large scale factors.