Thank you for the explanation @timcliff.
If a backup witness is voting in a way that the stakeholders like, and the top witnesses are voting in a way that the stakeholders don't like - then the backups may be voted in as the new top witnesses.
Whilst this is true in theory, from what I've read about the amount of power the top 20 witnesses have and how they vote for each other, it doesn't seem very likely that this could ever happen in practice, as things stand currently.
Until very recently I thought that witnesses got their spots in the table by number of votes. I didn't realise that power voting came into play.
Given that scenario it's hard to see how smaller stakeholders could really get themselves heard. 😊