Since the end of Fall season, clubs have had open tryouts for ECNL, DPL, GA, EA, EA2. They will not sign players for SOCAL leagues but verbally told parents that the offer will come after the Feb 13 date. Clubs definitely use this loophole to recruit players and technically conforms with the rule.
Another way is to give out coaches contact info. If a player/parent showed up to practice and did not disclose their club affiliations, then technically it is within the rule as well. The coach is not required to do "background check"
on a player and there is no rule saying a player will be "banned" from SOCAL league for training with other team.
Thanksgiving camp, holiday camp, and any other camps are 100% legal way to recruits as long as there is no contract offer.
It is possible that this club has been signing official contract agreement with players from other SOCAL club (signing up AYSO or other non-SOCAL is fine) and some parents leaked out that info. Other clubs found the evidence and SOCAL has to make a decision.