That's what slaves are.

Don't you tell me.
Do you suppose I don't know a slave's face when I see it?
Why don't their masters see that they're better fed and better clothed?
Tell me in three words.' No one answered.

The wage-system of modern England is a little difficult to explain in three words even if you understand it--which the children didn't.
'You'll have a revolt of your slaves if you're not careful,' said the Queen.
'Oh, no,' said Cyril; 'you see they have votes--that makes them safe not to revolt.

It makes all the difference.

Father told me so.' 'What is this vote ?' asked the Queen.