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I think by asking if somebody should take the bet in your hypothetical scenario, it misses the point of why we should take spots that are +EV. It wouldn't really matter if you're just allowed to be in a +EV spot just once then nothing. It's all about the long run and taking on enough of these spots to make some profit.
But if you're just asking for the sake of asking..? Sure, why not, it's like a value bet for a mispriced underdog spot in sports betting.
Not sure if I understand you correctly. Of course it does matter (a lot) if you only have one opportunity of making a single +EV bet. If you could do it multiple times then it's a no brainer - absolutely everyone would take such chance.
But when there's no guarantee that similar opportunities will ever arise - that's a whole different story, after all, you are still more likely to lose than to win, so there's also a logic behind not taking that bet.
As mentioned in the posts above - I'd be definitely in favour of taking a bet, but not sure what would be the most sensible approach in determining the right stake for it (or for mispriced underdogs in sports bets).