In brief, I believe that shutting down the shop, without warning, a day before maintenance is worse for the playerbase as a whole than whatever additional damage the exploiters could do in those 24 hours.

The two cases that stand out are those who planned on transferring ships (either lose out on 2 weeks of progress on new ship or have to eat shop losses) and those selling market items whose value will predictably decrease after maintenance (e.g. Val weapons after the new collection folders launch).

I'm sure I'm missing something, but it's just hard to imagine what would have to be fixed for net welfare to improve by closing the shop 24 hours early (e.g., fixing duplication benefits a few lucky/wealthy ARKs while increasing costs for the rest). On the other hand, the benefits to Sega of closing shop early are easier to fathom - duping decreases demand for scratch tickets, as does the ability to sell unsellable items. Though if the rationale is really to save a few bucks from one more day of exploits it just doesn't seem worth the PR hassle... But I'm making a lot of assumptions here so there's plenty of ways this logic could be wrong and I hope it is!

TL:DR - My suggestion is to either give 24+ hours notice before closing the shop or wait until after maintenance and ship transfers have gone through.

I'd add that it would be more preferable to take care of it during maintenance itself. Serious even give us a heads up we discovered issue with the shop so we're extending dt to address them. Id rather have them have a single longer dt then repeating shutdowns. That's just me though.

they need to take it out because the damage those exploits can cause, because they will spread all over and taking even more time to fix the issue and who knows what kind of damage that could cause, is bad for the economy of the players but is better that than having itens removed from you or even worse having your account banned because you bought one of those

Definitely agree that it needs to be taken down and fixed, just questioning why an exploit that was seemingly left for at least 13 days couldn't have been left for 14 so as to not negatively affect the vast majority of players who aren't cheating. (I can moreso understand not giving us advanced warning so that the exploiters don't take action and liquidate their inventory)

I also agree with you that losing purchased items (without a refund) or having your account banned are serious risks that you'd like to remove asap. However, I'd fall on the side of suggesting that Sega be very conservative with punishments related to an exploit that they shipped. If you can confidently identify the actual exploiters then ban, but otherwise take the loss, learn from it, and keep tabs on accounts that were suspicious.

An emergency is an emergency. A duplication exploit was found and it was immediately taken down, they thought they fixed it but a different one came up. Blame the cheaters and exploiters, not SEGA. SEGA is trying to maintain the integrity of the game so our items don't lose value in the long run.

@Rang-Dipkin is kind of difficult to the development team know if what they did really fixed the issue, this is a live service game so they don't have enough time to run and check if what they did so is more not having enough time to fully check if it won't happen again or the fix wasn't enough to solve it