It depends on how comfortable the trainer feels about running group/boot camp classes. I personally don’t have any certification as a ‘group’ instructor, but I have been running boot camps for 6 years now. I have been and instructor for police SWAT units for a few years, which involves instruction of a large number of participants in each class, so instructing group classes and boot camps was not a difficult transition for me. But that’s me. Keep in mind that you’ll have to multitask (continually making the class format interesting and challenging, as well as correcting and/or modifying exercises for multiple clients at once). If you feel comfortable teaching boot camps then maybe you should give it a try and see how it goes. Better yet—before you start offering your own classes, maybe you could sub or work a few hours for someone who is already offering boot camp classes to see if this is something you want to get into. Or you can do it the way I did it—start training smaller groups (3-5) and when you get comfortable with that number, add more participants until you get used to training larger groups. Usually 10 participants per instructor is a good number, which helps you maintain control and make sure you give everyone a fair amount of attention and instruction.
I hope this helps.