What is illegal under RLA: During negotiations neither party can change the status quo. If pilots picking up OT prior to negotiations, then suggestions from union pilots to not pick OT would be illegal (changing status quo).
To suggest a fellow pilot not pick up OT when NOT in negotiations is legal. This causes much confusion.
Example:
The Delta case scared alot of the union labor atty's because it DID make it to court. Many of the labor atty's working for the unions seem to have the OPINION that it would thus be ruled illegal in a court at any time. The ABX case was strongly on the side the pilots to not do OT or JA and 6th District Federal Appeals Court agreed that this ban was not illegal because they were not in negotiations. Hope this helps. Pilots and unions running scared again...