Richard Harrison wrote:

At a short or an open on a line , it is the current or voltage the
discontinuity generates which turns the wave around.

That is more or less true. But the claim being disputed here is the
other way around; that voltages and currents generate discontinuities.

If a virtual condition can generate the energy surge or
escalation needed for a reversal in direction, it is as acceptable as a
real discontinuity, in my opinion.

If it can do that it is acceptable as a miracle, in my opinion. :-)

73, Jim AC6XG