Depends on who it was. Someone I'm personally friends with and we have 4 other people who are 30+ and have good weapons and a butt-load of experience? Yeah, no problem. Joining with strangers from the forums and someone thinks the might be able to do it? Nope. I'm out of that raid after 2 wipes.
Um, realistically its not a good idea, only because for every level below the raid that you are...... you do %20 less damage, so if you try to enter the VOG level 30 raid you would do %60 less damage than normal if you are level 27. You should level up more and get maxed out upgraded weapons.
A lvl 27 would do 50% less attack damage than a 30...
I guess it would be no different than running it with 5 level 30's, since one dude always seems to die in the first minute of each stage!