i probably made it back in '09 or something has never had a subscription, i dont think its ever been online. its gamerscore is about 40k right now. so, lets say i modded another 40k (no online cheevos), then went online, would they immediately ban it? i know for new accounts they probably would, but since its so old i'm not sure. heck, i dont even know if they can tell if it was made back then.
Wait, if it's silver, don't mod it, you'll get banned eventually. Plus it'll be a waste of legit 40k GS. If it's an offline account (able to change the name unlimited times, not connected to XBL in anyway), Then YES! Do it! Like you said, only mod the offline achievements. After you're done changing your GS and stuff, bring it online. You won't get banned cause they don't know if you modded it or not because... It's never been connected to XBL! Hope that somewhat helps! xD
In theory, you can mod 100k worth of GS, but only if it has never been online (or offline for years) and you only unlock offline cheevos, and still be safe but it's a risk you must be willing to take and you can only blame yourself if it goes tits up
has it ever had silver or has it been hosted only on the console itself? if its been hosted only on the console itself it might require a gamertag change when you go live and could then count as a "new gamertag" even though it is years old one thing you could do is have a backup of it before you go live with it mod it to your hearts content then go live if you get banned use the non modded back up then go live with that and voila fresh and new could literally do it forever until you either mod it and never get it banned/reset
it has never been online at all, not silver or anything. when i decide to go online it will make me change my gamertag. however, if i do make a backup of it, and it seems to be ok online for a while (not sure how long it would take before i know i passed and will be ok) can i use the backup to create another, and essentially offer a service?
i believe you should be able to use the back up so long as its never been used online and doesnt have any specific information cause it should be able to be rewritten with console id's if need be, i havent tried this myself personally so i cant say wether or not it would work but itd def be worth a shot a couple times for you to test then if it works it could be used for a service