In the rule book it says:
the line is out.
It also says: the disc must be completely and totaly surrounded by out of bounds.
What is the line?

I think the bigest part of the confusion was the old non-rule that said "if any part of the disc is touching the line, it's inbounds." While that was coincidently true in the past, it was not part of the rule. The rule was that a disc had to be compeltely surrounded by OB area. Since the line was formerly considered part of the in bounds area and always the outermost edge of inbounds territory, anything touching the line was not completely surrounded by an OB area.

In the past, touching the line didn't make the disc IB. The disc not being surrounded by OB area made the disc IB. The same is true now.

The real boundary has no width or grey area. The effective edge of the boundary is the inbounds edge of whatever is designated as the "OB line".

Think of it like a course where the sidewalk and beyond is OB.
The sidewalk is really the OB line. The transition point where the sidewalk and grass meet is the boundary.

The rule has 2 parts.
1) A disc must be completely surrounded by OB area to be considered OB.
2) The OB line (if it has any width) is now considered part of the OB area.

So, if the sidewalk is out, and the whole disc is on the grass, but touching the sidewalk edge, that out or in? According to the rule.

I took the line as if the whole disc is out but touching the grass or inbounds, would be out.

The definition of OB hasn't changed: the disc must be completely surrounded by OB to be OB, so if any part of the disc is touching IB -- you're InBounds. the new rule says the OB line itself is OB so simply touching the line is no longer enough -- to be Inbounds the disc would have to be at least slightly touching the grass in the example above, though the disc could be 99% on the sidewalk and only 1% on the grass

So, if the sidewalk is out, and the whole disc is on the grass, but touching the sidewalk edge, that out or in? According to the rule.

I took the line as if the whole disc is out but touching the grass or inbounds, would be out.



The sidewalk is out of bounds, the disc is touching the OB sidewalk, but is wholly (or partially) on the inbounds grass.

The disk is inbounds because it is not completely surrounded by OB, even though part of the disc is over an OB area.

The one big difference i have noticed between the old rule and the new rule is now when you hit a wall that is declared the OB line like the one pictured below that lines the green of the 1001 ft hole 15 at Idlewild:
http://www.cincinnatidiscgolf.com/images/CoursePics/Idlewild/Idlewild15b.jpg
you must* take your lie from the far side of the OB creek because that is the last place your disc was InBounds (now that the line itself is considered OB). That is also the way the designer of this course has always prefered the hole be played.

*technicly when you go OB you can either take the last place IB as your lie or you may return to the previous mark (or tee) and re-throw plus the penalty stroke.

That's a sweet picture. It would be nice on a teeshirt !!!!