

Speaking as a player that doesn’t use proxies, if the people I play with suddenly all started to compete with stronger and stronger decks using proxied cards, I’d feel more likely to quit playing with them than try to keep up. Not everyone is looking for power.
The idea behind a ransom is that all parties need to believe with certainty that as long as money is exchanged, then nobody gets hurt. As soon as there’s doubt about getting paid or about being released, then suddenly there’s turmoil for any other party to hold up their end.
If I’m told I need to pay a ransom to get somebody freed but I know they may not be released even after I pay, then I may not pay. So it’s in the captors best interest to always release them upon receiving payment.
Then again we’re dealing with desperate, possibly evil people with no sense of morality and who will never have considered game theory before. Real life is messy.