Arrr!

(AFAIK) Gypsys have earrings to pay the ferryman ...
The ferryman being the one that ferrys them over the river Styx ... when they die

so I expect the traditions are related somehow

Even oder texts ( I won't mention the name) state that earrings were a symbol of servitude whether voluntary or obligatory servitude and the earrings must be worn for the endentured period. So a question of mine would be: did all pirates wear earrings or was the captain excluded? And it has been noted by several sources that servitude in this life enhances something or another in the crossing over...so that would be consistent with their associating the earring for a sybol of barter crossing over.

And as far as the Gypsies aren't they just pirates without boats? Ha - no offense meant to any modern day gypsies.