"Much good in your 'if'". Your if is somewhat flawed, isn't it, Alec? Because we have seen running, we have run, and we can tell time, and we know what four minutes is. We don't have to experience every single experience at first hand to know anything about it.
Also, aren't you rather presuming that "enlightenment" is a permanent condition? Rather like being awarded a PhD, you get "enlightenment" and you got it and you're done? Are you quite sure that that's the case?
Mary, it was an analogy. Clearly "enlightenment" is not something we see, at least not nowadays. All the enlightened people spoken of were in the past, either it doesn't happen anymore or we have lost the eyes to see it. You are correct that we don't have to experience everything to know anything about it but watching videos of swimming in the sea will not really prepare you for swimming in the ocean, does't tell you about the power of the currents, the nature of buoyancy, how strong you will need to be, etc.
Since i only have stories as criteria, yes, I presume that enlightenment is a permanent state. the stories of the Buddha do not include him "retaking his exams". Generally, in my home anyway, lights that have been switched on don't switch themselves off unless they blow.
Anyway this all just intellectual waffle isn't it?