If you don’t extend your contract with the operator technically it’s not your money anymore, it’s theirs.
They may decide to give it back to you but they are not a custodian.
Discussion
If by "technically" you mean according to consensus rules, I hope you realise not a soul cares about that, not users and not regulators.
Just because people send sats to custodial LN providers addresses, doesn't make that a donation.
You designed this contract (I presume because that is the best you can do with Bitcoin smart contract), but you didn't design it to enable time bomb donations to operators... that is bug not a feature.
Unless of course you do advertise Ark as a time bomb donation to operators, then good luck with adoption and actually good luck with regulators still.
No. The contract involves the operator funding an output onchain for you. You are responsible for rolling your claim over to another batch. If you fail to do so, the operator will sweep the output at termination of the contract as originally specified. The operator keeps no account of its users unlike custodial services.
Ok it is nuanced I will grant you that, but I think our goal is that users can receive bitcoins without any more of a ceremony than having an address, and that money remains passively safe somehow, even if by employing a watchtower, as long as this watchtower can't steal (only fail).
This is the least people expect from payment systems.
However, operational/maintenance fees are acceptable, but losing all the funds wholesale on a such short timeout is just not going to fly.
My baseline is Phoenix LN wallet where presumably the worst that could happen is they close the channel and I pay high fees, or they try to steal and a non custodial watchtower can bail me out.
If Ark is a step forward (no need for opening channels) I hope there are no steps backwards on the other end.
Operators run a business, it would be ill advised for them to run away with user funds even if users leave their outputs to expire. Of course there are plenty of mitigations for this but it's not a dealbreaker.
Cashu mints run a business too, but reputation usually begets KYC, and dark markets beget rug pulls.
The best argument I read so far is that some ASPs could offer longer expiration periods with higher transaction fees, and users can use that for long term savings.