I think it's great that they made that CG open only. Hell, I wish they'd do more of it. All CGs open only, and all PP stuff open only *AND* add a credits bonus of say 10% to all activity done in open in order to compensate for the slightly higher risk involved which in turn results in less profit due to sacrificing some cargo-space/jump range for proper defensive and offensive modules, and of course the occasional rebuy due to PVP action.
In Elite: Carebears Edition (solo/private group) one can min-max without any discernible risk. In Elite: Dangerous, ie open, not so much.
Having played some 99.99% of the time in open, I can't say I've been overly bothered by player interdictions. Most I meet, I throw a salute. Some even salute back. Then there are the random chats when docked or by chance meeting some stranger down on a planet or wherever. Most playing in open are quite friendly and have no ill intentions.
Nearly all my rebuys have been from quite willingly going into battle. Wing(s) vs Wing(s), and having extensive PVP experience I know how to be prepared and handle myself on the rare occasion I get interdicted when going about my daily business - which these days center around gathering materials and data for upgrades.
First rule of open is that you accept the risk. In that regard, I'd consider both menu-quitting and yanking the plug/force client shutdown to be cheating. FD went a baby-step in the right direction when increasing menu-quit (when in danger) from 0 to 15 seconds. But it is still too short. 30 seconds would be better, a full minute ideal. so what about the plug-yankers and ctrl-alt-del crowd? From a technical point of view, it is entirely possible to transfer a ship instance from one client/instance to another. How NPCs work afterall. So if the client suddenly goes offline, the players ship is treated like an NPC that is dead in the water for a minute before disappearing. Should it be blown to bits, the next time the yanker logs on, he's met by the rebuy screen rather than an empty instance.
Second rule of open is that you go nowhere without the means to get out of a sticky situation or fight back. None of my ships zoom around with minimalist shields or glorified laser-pointers for defense. Grade A shields of biggest or next to biggest size that will fit is in order. As are Chaff, Point-Defense, Shield-Boosters and even SCBs, even if just a tiny one to hold over until one can flee.
Third rule is to have friends to help out. To teach you how to fight or flee properly, and if need be wing up and provide mutual support.
This is getting long, but I'll end with a little anecdote. About a month ago I got interdicted by a player for the first time in a long time. I was just minding my own business, getting back home from a mining-trip in my Fed. Dropship, cargo full of mined goodies I needed for some engineer upgrade or other. My assailant was in an FDL. No need to panic, just submit, hit the boost button a couple of times until the FSD was cooled down and jump to another system (no masslock then). Jumped back again, FDL still there, but out of position to re-engage. Made it to home-station, picked up my Corvette and the assistance of two friends in FDLs, winged up and went hunting.
Through our extensive intelligence network, we learned his position. He was lurking in a neighbouring system trying to do the same to other people. We soon found him there, interdicted him, and proceeded to promtly turn his shiny FDL into space-dust. He actually respawned at our home-station, as that is where he last docked. We found him there as we went back to get out of our PVP ships and back into our doing-business-ships. We had a nice little chat, no hurt feelings or anything. All happy and had a bit of action. We've not since seen him trying any funny business in our home system though
And happenings like that, is why I play in open. Yes it is more dangerous, but also a lot more fun.
