I'm not sure what platform you are on, but if it's Steam, most of the people at the G6 level are cool and send naked hunters. There are a handful of tryhard d-bags that like to send fully equipped hunters, but you get to know their names and then if you're not equipped to deal with them, you can just use the escalators to get rid of them. I'd tell your the usernames that I remember, but they might be members of this forum, so I won't do that publicly. I know one of the names on my shitlist participated in that Steam Trials of the Tower challenge (thankfully they didn't come anywhere close to winning), so they might be a member here. If you're on Steam and you're curious who those people are, you can send me a PM.

When I played through the game, I would unlock the next level of fighters as soon as I thought I was able to. I wanted to make life easier on myself and in turn give myself the best chance to climb the tower. I could care less about trying to trick people in TDM. And that's really the only reason I could see to not unlock the next level of fighters. The G6 all-rounder will make it that much easier for you to make it to 50 so that you can unlock more G6 fighters and start gearing up to take on Tengoku.