Hi, hmmm, yes, the question is now where to add such "protection" - into component (all payment plugins will be invfluenced without having the option to change it) or to plugin options where only selected method can set such behaviour.
Are we 100% sure, there will be no case that the payment plugin will be used even with zero amount (e.g. some kind of registration, etc.). Unfortunately no experiences now, so really hard to say.
The second idea is, do we really need such parameter when we can easily do it in payment options:
Jan