Perhaps some kind of service where a {node A} can advertise a sidekick/spillover channel address, that sats can pour in to, if there's no capacity into {node A}. The sidekick/spillover addresses could be run by custodian whom you would have to trust with small amounts, for small durations (until you sweep the sats out). These services could charge maybe 2%-3% (auction market) to sweep sats back out.