Even with the extra width of the pannier the back left edge will still be further away than your hips, arms, and handlebars. VERY unlikely someone will hit it that wouldn't hit you anyway.
That said, it does make the back of the bike look wider and people generally do give you more clearance than if you mount it on the other side.
and move your light so you're not blocking it!!!!! I mounted mine on the back of the rack so there's no chance of blocking it.
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"There is no greater wonder than the way the face and character of a woman fit so perfectly in a man's mind, and stay there, and he could never tell you why. It just seems it was the thing he most wanted." Robert Louis Stevenson
