I think it would be hilarious and entertaining if brawling pits:
*Prohibited all equipment with the exception of handwraps and cloth.
*Prohibit all spells, bard songs, etc when in the pit, with the exception of feats such as Trip, Stunning Blow, Sap, Stances, etc.
*Only flag you for PVP if you met the above requirements
Then we'd had a real tavern brawl that would fit perfectly in the D&D/DDO universe. After all, we've got Death Match and CTF for anyone who wants to go all out. Why not have a real tavern brawl?