Had one while I was leveling that didn't even have anything in the off-hand slot.
Just to be nice, and to save myself some work (as I was the Healer), I had one that I had just finished for my tank companion, who used the same stats as him, so I traded it to him and he still didn't equip it.
HAHAAHAAHA Been there. Was doing a HMFP FE, I think, Tank had 13K HP, so inspected. He had level mainly level 49 gear and no implants. I had just made a pair for my wookiee and gave them to him for free. He tanked me and said he could really use some for his healer, so I gave him the pair I made for Risha. His HP never went up during the entire flash point. However dps was overgeared so it wasn't that big a deal and we finished with only him dying a couple times getting fluged off the side of a couple platforms. Saw him the next day on the fleet, his HP was about 15K HP, but considering the gear he had got and the implants I gave him that seemed low, so i inspected. He was wearing the implants alright, not sure how much good the cunning was doing him, but he did have the impants on and didn't just sell them on GTN.