@Axel-P - I am in favour of that one,
One workaround for this could also be to either A. give a task step (validation) to a group of users /userlist, and if one of them validates, it is good,
Or - B., same as A., you add somebody (like yourself) (temporarily) to the userlist after the workflow has already started.
Does that invalidate the validation or signature process?
I would say no, In the end, if for example a signature is required, the question if anybody accepts the signature goes beyond the actual workflow; if the validation by somebody stepping in, is accepted by the person doing the signature, depends on the process and the reality of the organisation using the process.