Source: The Wrestling Observer Newsletter
According to sources, the RAW Battle Royal main event to crown an opponent for CM Punk at WrestleMania 28 was a last minute idea that came from Vince McMahon. Although WWE officials had been planning for months that they were going to do a CM Punk vs. Chris Jericho match at WrestleMania, they just weren't sure how they were going to get there.
One idea discussed over the past several weeks was that Jericho would insult Punk so bad that Punk would eventually wind up demanding a match between the two. WWE officials decided that the storyline was too close to what they were doing with The Undertaker vs. Triple H storyline so they went a different route.
There were also discussions about fans who just paid to see the Elimination Chamber pay-per-view to determine the WrestleMania main events and having Jericho throw insults to get a title shot would devalue the Chamber to fans.