If I wasn't sure I'm an idiot I'd post this on delving:
If I require a channel with you to send onion messages to/through you, I have something to lose should I do it too much. afaict There's a weak but non-zero sybil resistance to onion messaging as is.
What mechanisms for sybil resistance will this overlay have? It'd be easy enough to require presence on the channel graph, but if I don't have a channel with you, how will you punish me? Personal banlist/reputations? A gossiped banlist/reputation? PoW? Payments? Some combination?