Regarding the suggestion itself, I'll be positive, and here's why.
A few days ago, I attended a CE and was amazed by the amount of placed barriers. They literally were put in a very bad way, preventing cops (I was a cop when I attended that CE) from running back to their spawn, also preventing criminals from rushing. This is indeed abusable and needs to be fixed as soon as possible. In my opinion, I guess that if you want to place barriers, you should have 500+ hours. However, if this restriction already works inside the CE area as well and people are still misusing barriers since it pops up to players who try to place barriers outside the CE dimension telling them their inability to place barriers just because their hours are less than 500 hours, then, I guess that we either increase the hours from 500 to 1000 (number can be negotiated) and/or create a warning, which could be: 'Beware, you're about to place barriers. If you somehow misuse them, you might get admin jailed. Be careful!' and translate it to the barriers' placer's guy.
And by the way, I don't agree with allowing PCs and CBs only to place barriers, as they're not always online leading their teammates, so another player needs to do the job instead.
It can be restricted to more trusted people who wouldnt risk getting punishment over a barrier.
RCM+
No. Imagine a civilian whose community rank is RCM+ as you're saying, tries the Law side and obviously has no idea about barriers because, simply, he's 'new' to playing on this side. He decides to place barriers as an intention of helping his teammates, however, out of nowhere, he gets jailed for something he didn't even try to misuse in the first place. Wouldn't this be unfair?