Dear Dan;
I would think it would be in the "hands of the operator". I have no 'real world' experience with dynos.
I know in the early 80s I took several vehicles we had passed at our shop to a State contracted SMOG testing Corp. and they all were failed on the Dyno.
When I returned they still met/passed the required specs./limits (non Dyno.).
This forced us to re-test them at further expence in time to us and money to the customer. In fact; we had to lie on the paperwork to pass when the cars were "clean" under the existing laws.
I filled several complaints with the BAR that year on the testing station, with zero results because the shops owner wouldn't go to the court hearings etc.
I doubt a dyno test could damage a transmission but someone else might know better on that.
