By the early to mid-1990s, solo divers became more visible and increasingly open about their alternative dive safety philosophy, despite the recreational industry's established adherence to the buddy system. It wasn't until 2001 that Scuba Diving International (SDI) initiated formal certification training specifically for solo diving. Several other agencies eventually followed suit with certificates titled Self-reliant Diver and variations of that theme; all with the intention of improving diver competence without necessarily going solo, and recognising that the buddy system does not always comply with the ideal. At the 2012 "Rebreather Forum 3", a significant minority of attendees were of the opinion that, in some circumstances, it would be acceptable to dive solo on rebreathers.