Is the Runner allowed to invoke abilities from cards which they do not need in order to add a credit to Net Mercur?
For example, let's say the Runner uses their last click to run on Archives (which is unprotected say) - during this run, can they spend a credit from a Stealth card which they do not need to do for any other reason than to add a credit to Net Mercur?
I'm assuming the answer is yes, but answers using any reference material to support their statements would be appreciated.