I've played and ref'd enough indoor CQB games to know that wearing anything less than full-skin coverage and full face protection is stupid. Partially because you just end up hurting yourself by having your arms shredded, and partially because you can't trust anyone to play safely, especially when they're new.
New or inexperienced players will, on average, nearly exclusively use full-auto and aim for 'headshots' because 'headshots are cool'. Some people of all relative skill levels also get scared and/ or frustrated and tend to retaliate in an uncontrolled over-aggressive manner when they're butthurt by losing.
Requiring full face protection and strongly encouraging long sleeves and padded gloves topped off with a 350fps limit isn't about accounting for what safe, positive players can handle, it's about limiting the amount of damage a moron or overwhelmed newbie can do.
I've played high-limit CQB with no cage against guys whome I've trusted and I was just fine. I would not, however, walk into an arena with people I didn't know and had not played with before without suiting right up and knowing all guns had passed a crono.