Strictly speaking, not by Army Regulation. That said, lower level commands may mandate that a soldier wear all earned ribbons/medals for various functions, inspections, events etc. Also, a DA Photo is probably one of the most important documents for consideration by all officer and senior NCO promotion, command and other selection boards. A discrepancy between the badges, tabs and awards worn in the photo and the supporting documents in the file would generally be regarded as a pretty big negative (usually in reverse though, for awards worn with no supporting documentation).
At least part of the thought behind that is that an officer or senior NCO, responsible for keeping their soldiers squared away, should not have his/her own personnel file in disarray.
Joe 6-pack wrote: “At least part of the thought behind that is that an officer or senior NCO, responsible for keeping their soldiers squared away, should not have his/her own personnel file in disarray.”
More importantly, it was an easy way to distinguish between candidates for promotion. I’ve heard tales of those on promotion boards scrutinizing official photographs with a magnifying glass comparing awards with the paperwork.
An incredibly lazy thing. If I were in charge of a promotion board and I caught someone doing this, they would have been out on their ass.