I like the back-and-forth of this thread.
As an Instructor, I've had "assistants" work for me that were new, themselves, to being an assitant. Most are great, but there were one or two that I'd never have assist me again, as they were not technically proficient, and flat-out gave wrong information to students.
Most dive accidents happen on the "first dive of the series". This is true for any dive level (DAN has the studies to back this up). Basically, if you go diving, and haven't done so in awhile, best to start slowly. Refreshers are recommended if more than one year.
There is an inherent trust in new divers and DM's. When I was a newbie, a newly minted DM managed to lose my youngest daughter (surfaced without her). Not a good situation.
But as an instructor, it is important for new divers to communicate the fact that they are new to the DM and/or boat operator. When I do dive planning, I use the "weak link" theory, wherein everyone should be able to do a dive. Taking new divers to Devil's Throat in Coz is assinine and endangers the group as a whole.
But when I teach divers, I teach them also to ask questions, and to have situational awareness. They are encouraged to speak up, while signing up, for trips. There has to be a give-and-take with divers and operators. No one benefits if a dive incident occurs.
But it is also a two-way street. If a DM or operator asks your skill level, be honest. If you have 100 dives in 10 years, I'd still say you don't have much experience. More relavent are your bouyancy skills, and some people nail it after 3 dives...other never. I have seen people with 300 dives that are awful divers- no skills, no buoyancy, no navigation, swim in poor position, etc. But I've had newbies work and work and work, and I'd take them diving with me anywhere. A lot of it has to do with comfort in the water, as well as the skill set. But if you are asked, be honest!!!
Great discussion.