1) If they were to do that, wouldn’t it be more transparent than other pools? It would be more provable  that this occurred?

2) As long as they are not doing that, I’m not sure that would constitute a custodial relationship. At no point do they put bitcoin in an address they control that belongs to someone else. Courts might need to broaden definitions of custody to include that. But legal experts in this area would know more than me. Now, if they do at some point withhold funds, there could be a debate whether it’s custodial failing or a breach of duties.