"Probably irrelevant, but this pic also reminds me how difficult it is to judge height above still water, with no winds, no ripples, no waves."
Pics of rescue work show many small bits of ice on the water.
As to the passengers being risk takers, asking the pilot to do risky things is irrelevant, even if the passengers had the knowledge to evaluate aviation risk in that environment. The only thing that matters is the pilot's willingness to take risks. He ran a sight-seeing business, and would be familiar with crazy requests from tourists - and politely refusing them.