Being strict with the uniform code didn't make a lot sense considering the fact that Neelix and Kes (and later Seven and Icheb) got to put a communicator on whatever they were wearing that day. Those former Maquis didn't chose to be part of Voyager's crew, they were civilians stuck on the ship and should have had the same option to wear civilian clothing as other civilians on the ship.I think Tuvok was extra strict on them because they were, basically, going through basic training in order to be integrated into the Voyager crew, afterwards, once they had earned their field comissions they probably their earring and hairband privileges back.
And it's not like Neelix showed perfect behavior at the start when he took over Janeway's dining room without permission or barged onto the bridge uninvited. He was basically a bum who tried to make himself useful when he clearly wasn't, all he did was cook crappy food and his knowledge about the quadrant was basic at best, you're telling me Voyager couldn't some copy of space wikipedia from some friendly species instead of relying on Neelix?
Gerron should have replicated a Neelix outfit and should have attended the next senior staff meeting chewing on some leola root, saying he assumed he was welcome if he dressed appropriately.