There's a cruise ship that needs to have a certain weight in order to not capsize. That weight threshold happens to be at 50% of the population (for whatever population we're considering in the original question). If the ship capsizes, everyone on it dies.
You're given the option: either get on the cruise ship or don't. Not to take an actual cruise, not for some other intrinsic prize, just file on it for a minute and then get off.
I don't see how those who refuse the risk of dying on the ship are complicit in the deaths of those who willingly choose to hop on it knowing the risks involved