Since Rebecca’s costume is just that bad and we got many reblogs and notes explaining how it is justified by her gladiatrix status, I figured we can as well revisit it, put it through a bingo and elaborate how it’s not a fool-proof excuse for a battle bikini.
wincenworks already talked about it here, so to make it brief: as much as gladiator “armor” was supposed to leave them vulnerable (especially if they were of the “punished-by-fight-to-death” kind), it was still within area of plausibility.
Rebecca’s costume just doesn’t make any sense on far too many levels: Why the bikini, but not toplesness? If she’s sent to lose in a fight, why give her a shield and weapon? If her “fighting” technique is all about dodging and she’s so confident to not get hit, then again, why the shield? And how does that top stay on?!
Considering she’s forced to fight in something as ridiculous (that is bound to fall apart), her male opponents should not be equipped with anything more practical than a chafing chainmail thong and nipple-pulling cape-ring-thingy. After all, just being bare-chested still would not make them equally sexualized as her.
Not to mention, even a quick research proves that many characters that fight with her get to keep their normal (at least by One Piece standards) costumes.