Auto-fill "Collection time" with a "Set to right now" button ?

[simroux]

This would be a similar UI as "Set to today" for "Collection Date" except it would set "Collection Time" field to the current time (in the right format and the right time zone).
Not sure how to deal with the fact that the timezone we ask for may not be the time zone of the user, so either auto-convert to UTC (which may look confusing) or make sure the schema also accepts time zone info (but then auto-fill would be even more helpful as that'd be one more unusual data to enter in a controlled format that may be confusing for users)