It is an accepted practice for veterans to wear either miniature medals or just the ribbons on a PC or on a military style shirt in a less formal state. There are no specific rules other than you would display them in the same manner as on a military uniform. In order of precedence and in a neat and orderly manner. You will see khaki shirts at games and gatherings with ribbons and at more formal occasions such as dinners you will see PC's with either ribbons or miniature medals displayed. It is legal to wear these as long as they are your own awards. Many who wear these also add awards such as marksmanship awards or jump wings and such.