I was playing with some features I don't usually use within collector. I had a service with some fields to collect measurements. I wanted to add in a hint for how to measure which I hadn't done for a service being used in collector. When you add a hint, in AGO it will display the hint when you hover over the field when adding it but when you goto collector the hint is the only thing you see, ie the field name is no shown just the hint. Do hints not work within collector? If not I would think they should just not be shown instead of replacing your alias.