I'm a big fan of the safety triangle, especially commuting in the dark and dreary months, and for touring. Easy to attach to a pannier,

but here's one fastened to a spoke zip tied off a rack which i think is a great way to attach one... I put down a LOT of dreary, wet training miles on this rig




and TWO on this touring bike, one on the skis higher up, one on the pannier.