In the interpolated signal there is a dead give away that the ringing is due to some kind of digital filtering / interpolation: there was ringing before the transition.
Yes, i should have mentioned that.
Yep.
Needs emphasis: Anything before the rising edge is from the oscilloscope's interpolation, always, not from the signal or the probes. It will probably have a counterpart at the top of the rising edge, too.
That is incorrect; preshoot can occur in the analog domain as well. For instance lumped-parameter transmission lines create preshoot when excited beyond their cutoff frequency and this is visible on some analog oscilloscopes like the 300 MHz Tektronix 2465 and following models which pushed the capability of their delay lines.
It is easy enough however to distinguish this from the Gibbs phenomenon which is symmetrical around the transition.
Back when DSOs were new, Tektronix had an idea for detecting the problem Dave showed.
The processed trigger signal can be used to estimate the frequency content of the input signal. If it approaches or is greater than the current Nyquist frequency, (1) then it is very likely that aliasing has occurred and a warning was displayed to the user. This idea completely failed because it made it seem like Tektronix DSOs suffered from aliasing more than their competitor's DSOs, which they did not, so it was quietly dropped.
I seem to recall using some DSOs which displayed a warning when interpolation was used to fill in the display. That seems like an easy solution but no doubt it suffers from the same problem. Again, marketing triumphs over engineering.
(1) Or if any trigger period is less than twice the sample period.