I have only encountered griving once; it was in the form of spawn camping.
I was playing solo and a galleon engaged me near an island. One of there crew managed to board my sloop and kill me. I didn't have any chest or anything else of value so I wasn't too concerned. I respawned on my boat only to be killed again instantly.
How did I deal "deal with the griving..."?
I scuttled my sloop a few moments before respawning again. Once I respawned in the water I saw the fellow who had boarded and killed me twice swimming away from me. So I started to swim after him. He never noticed he was being chased. Their galleon came to pick him up and I managed to sneak on board right behind him without being noticed...
I went straight to their captian's quarters where I found sooo many chests. I knew there was no way I could win a fight against 4 of them and I didn't have a way to steal their treasure for myself...so I decided to grieve the grievers...I brought every single chest they had (it had to be 8-10 of them) to the balcony that wraps around the captain's quarters and then chucked every last one of them into the sea.
A couple of minutes after I unburdened their ship they stopped at an island (presumably on the next leg of their voyage) where I made a suicide run at them. I didn't manage to kill any of them (nor did I really expect to); I really did it so I could get back to the mermaid. But I had exacted my revenge.
That whole encounter probably cost me 10 minutes of my time....God only knows how much of their time I tossed into the ocean.
I wouldn't have done it if they had just killed me once, raided my supplies, and left....But they spawn killed me.
That is how I deal with grivers.