Jim Kelley wrote:
"Are we then supposed to infer that it (the source) doesn`t re-reflect
the wave if anything other than a short or open circuit appears there?"

The reflection may be incomplete unless either a hard short or complete
open-circuit appears at the source where the generator meets the
transmission line. If the source appears as a complete short or open the
reflection is total.

Best regards, Richard Harrison, KB5WZI.