Loss of funds is not my primary concern.
I see a clear risk that KYC-free custodial LN wallets will go the way of the KYC-free exchange.
Discussion
KYC Free is largely an illusion.
No one cares about buying groceries with BTC, but at scale, buying a house after the next 20x, buying and taxing a car etc, you get KYC's then, and, if your Gvt is interested, the fact that, until then, you were KYC free, is moot.
I care about buying groceries with bitcoin. Government can and and should ask questions if large unexplained sums appear. That does not mean that we should be ok with every transaction beein de-anonymized.
There is still a value in moving away from the current system where all interactions with digital money is through companies with KYC requirements.
My fear is that we just recreate the current system but with lightning as a settlement layer. We should aim to win back more freedoms than that.
If you want privacy, using a literal ledger is a category error. Every attempt to load privacy into a literal record of all transactions is going to be, at best, a work around.
There are coins designed to be private, and I'm, happy to accept that they are, but BTC isn't one of them.
The State will decide how much privacy you can have with BTC - mainly of course, it simply doesn't care, until it thinks you are breaking laws to the extent that the effort is warranted.
We can never guarantee that governments will not make it illegal to use bitcoin in a pseudonymous way. Depending on technology we can make it more or less difficult.
For example, It is much harder to limit the freedom of individuals than it is to limit the freedom companies are allowed to give customers.
Further, torrenting is a good example of technology making legislation inefficient even if it actually becomes illegal for individuals.