The tweet is the wrong idea. "You'd need a huge debt for that to happen!" I SHOULD NOT INCUR DEBT IN A VIDEO GAME I HAVE TO WORK OFF. That's the literal definition of WORK as opposed to FUN.
The crucial part is that it'll happen based on real time. You don't play, you still have to pay the in-game costs. And don't you dare to get ill or some other unforeseen things happening to you and you are off for a longer time. The game is ready to punish you for that.
Because never has it ever happened to a game that somebody returned, found that he lost stuff and rather left the game and moved somewhere else.
Mind you, "never" doesn't include games like a MUD of old times, SWG or UO, where you also had to pay for upkeep. Or also AO for guild cities. But in those games the upkeep had some gameplay reason: areas to place houses or cities was limited. Houses of players who already left the game cluttered the landscape, blocking it for newer players. Upkeep was a way to fix that: if you didn't play for too long, the game cleared the space for actually active players.
There was an actual reason for having that. And still, at least in SWG and UO there were people returning to the game, finding that their houses and stuff were removed and immediately left again, never to return. That's the price these games had to pay for having such a system in place: drastically reducing the number of former players (so those who might actually have fond memories of the game and are likely to return and pay again), by punishing them for their absence. That's why later games switched the housing system to instanced versions. Instanced housing doesn't have the high cost of in-game real estate limitation.
In ED we are in space. For reasons unknown, there's plenty of space in space, so it's not like we're running out of space quickly. And if you still worry about places being crowded, just don't spawn a carrier any more when the owner wasn't online for a week. The reason why those games needed such a mechanic doesn't exist here. So I really don't get it, why we need all the disadvantages of such a mechanic, without even having the benefits?
If the goal is to have running costs on these carriers then rather demand docking fees, make jumping very expensive, stuff like that. That's costs added to players normal activities. They play, they do stuff, they can also stem the burden. But implementing costs for people being offline is just a bad concept. I hope FD reconsiders.