Inability to communicate is not required in the classical prisoners dilemma. It's inability to credibly commit.
The distinction is illustrated with the common application of the prisoner's dilemma to cartels. Cartel members can tell each other they will restrict production, but they do not observe each other's factories. So even if they agree ahead of time to reduce production, that is cheap talk... and they can produce whatever they want.
It's quite similar to this game show, though as a previous commenter pointed out, the relative payoffs are different.
I suppose this will have been discussed in other comments, but it seems to me the ability to credibly commit here isn't bad. I'm not sure if verbal contracts are legally binding in the UK, but they certainly have a lot of witnesses, and the social consequences for breaking a very public verbal contract can be substantial.
The distinction is illustrated with the common application of the prisoner's dilemma to cartels. Cartel members can tell each other they will restrict production, but they do not observe each other's factories. So even if they agree ahead of time to reduce production, that is cheap talk... and they can produce whatever they want.
It's quite similar to this game show, though as a previous commenter pointed out, the relative payoffs are different.