One of the things that seems to be an American contribution to the gondola world is the "message in a bottle".
Oh sure, someone a heck of a long time ago came up with the idea of placing a message in a glass bottle and casting it adrift - and there's a chance that it happened even before there was an "America".
Many guys propose marriage on a gondola these days, and many more celebrate birthdays and anniversaries on board - here in the US, the message in a bottle serves well as a delivery method.
Typically the gondolier will keep the bottle hidden on board the boat and place it in the water at just the right moment, in a place where he can double back on it.
In the shot above, we see a gondolier in Boston holding the bottle up (presumably for the photographer) before placing it in the water.
Because it's in Boston, you can see another striped shirt on board, being worn by the accordion player.