How is Cambridge University Press going to extort money from Agricultural researchers worldwide if they make the text of the article available for free?

From the Instructions for Contributors at the Renewable Agriculture and Food Systems journal:

Cambridge University Press accepts papers on the understanding that the work has been submitted exclusively to the journal and has not been previously published.

There is no mention of "Transfer of Copyright" but that doesn't mean it's not necessary.

Can the last politician to go out the revolving door please turn the lights off?