Why is it dangerous to hold a great amount of coins with LN? You're locking your funds on a multi-sig address that you can withdraw the final result cooperatively or uncooperatively whether your node wants it or not. Am I missing anything?
Apart from what pooya87 has already said, there are some edge cases which not many people know about. For example, if you lose your channel database, you need to initiate DLP (data-loss protection) in order to get your funds back. You can do it as long as you have a backup file which was generated after you have opened all of your channels. That file contains all the necessary information you need to reestablish the connection to your peers and ask them to close your channels. Here are the possible scenarios:
1) Everything goes well and all of your peers immediately broadcast the latest commitment transaction of each channel. You will very likely get your funds back after 144 blocks have been mined.
2) Some peer takes the risk and closes the channel with an old commitment transaction. You cannot broadcast a penalty transaction because you lost all of your data.
3) Some peer is offline and cannot respond to your request. Unless they come back online, the funds are locked up in that channel which means that they are lost in a limbo.
Good luck getting 50 payments request from 50 users to be paid before they expire! I'd like to see this happen though, it's better than creating dust inputs.
That's why
keysend should be required by the campaign manager. Unfortunately, it looks like it is supported only by LND and c-lightning so the participants would have to run either of these implementations 24/7.
1. The payment is not treaceable just like onchain transactions.
Something to think about for the campaign manager: without on-chain evidence, what will you do when someone claims not to have received his payment?
Each invoice contains a hashed payment preimage. In order to claim the payment (or HTLC to be more precise), the preimage needs to be revealed to the payer. Thus, the campaign manager could prove that the payment has been claimed by revealing both the invoice and the payment preimage.
A CM might even open one super LN channel for (example) ten week's worth of payments. The Campaign funder can see the balance being used to open a channel and that it's still open week-to-week as the campaign progresses.
Last week, the participants got paid over 0.19 BTC in total. Currently, most nodes reject channels larger than ~0.1677 BTC so CM would have to either open multiple channels or a single channel to a large HUB which
supports Wumbo.