Lightning definitely adds an interesting dimension to the USE of Bitcoin.
What I'm trying to wargame out in my mind, is if there is any market for selling "dirty" coins cheaper, to liquidity providers who DGAF about taint, and just throw all that tainted coin into Lightning, and watch the WEF and TPTB have steam and sparks coming out of their ear-holes because tainted coins they have tried to "outlaw" are actually being put to good use...
/brainfart
Well... This is a very interesting question, I think. And actually somewhat easier to answer than it looks.
Who have you opened channels with, and what condition were those channels in when you closed them?
You and I have three channels open together. So no matter WHAT is done with our channels, you and I will be the only ones to see the bitcoin at the end of those channel's lives. We could facilitate trade between millions of transactions among hundreds of thousands of parties, and when we CLOSE that channel it is still the 5mm each (I think) that one or the other of us put up between us. Those bitcoin have never moved. The ONLY thing different is who gets what at the end of it all. It is even possible (though difficult) that we both get back exactly the same sats we put into each channel only losing the value of the fees involved. And at the other extreme the other user could receive the bitcoin from the contract initially put in by the channel partner. In the latter case you would have another channel with another user where you gained exactly that much equity.
So far as layer one is concerned it's sort of like a poker game. You and I put money in the middle, and then one or both of us gets some of that money back out. The only difference is in the meantime our nodes could have agreed to thousands of transactions canceling themselves back and forth forever.
I have a couple of channels with partners where we have done magnitudes more transactions than the channels even hold. If I wanted to close those channels I could let the money all come over to my side, then close the channel effectively doing nothing. Back to square one.
So the point is if you open a channel with a criminal you might end up with bitcoin used in a crime previously. I personally see the opportunity to "launder" money on layer 1 with the lightning network to be fairly bad, unless we are only talking about very small amounts. Now moving money around privately without a clear link??? Well that is another story. I have a channel opened between the two nodes I run as well!
(Well I used to... I need to reopen it lol)