Justin Bieber -- I Don't Do Lines ... Wheelchairs it at Disneyland

Justin Bieber + wheelchair + Disneyland = I get to cut to the front of the line! Or at least that's how it looks.

Justin was at the happiest place on earth in Anaheim Sunday and posed with a fan while in a wheelchair. The girl posted the photo with the caption ... "I love how he just pretended to be a normal person on a wheelchair."

Of course, the immediate reaction online was that Justin was a line scofflaw ... but Justin's camp tells TMZ that wasn't the case. We're told Bieber was nursing a knee injury from basketball and only sat in the wheelchair to rest for a few moments.

Even more interesting ... we're told Justin wouldn't need the wheelchair to cut lines, because Disney already escorts him in and out of rides to avoid huge crowds gathering when he's in the park.