TLDR: Never mind, user error
It seems that whether I specify labels: { visible: 'false' } or labels: { visible: 'true' }, the label is always displayed. I would have expected that specifying false would not cause the label to display. Specifying another option, such as labels: { format: '{0:C0}' }, does not cause the label to display.
Here is a dojo demonstrating the issue. Note that both the second and third bars display labels, even though the second bar has visible set to false. The first bar, specifying a format for the label, does not have its labels displayed.
Hi Jay,
thank you for the update.
Indeed, boolean values for the components' properties shall not be quoted.
Regards,
Nikolay