Priority-Regression policy

[Graham Percival]

What's the feeling amongst developers about what should be ranked
as priority-Regression (and thus stop a release) ?  In particular,
should *everything* that used to work -- even if it was by
accident? -- be ranked a Regression?

For example,
- markup \note in time signature: worked in 2.10, currently
  Defect-Low.
http://code.google.com/p/lilypond/issues/detail?id=628

- Tie direction: worked in 2.10 (by accident?), currently 
  Enhancement-Low.
http://code.google.com/p/lilypond/issues/detail?id=592


I don't particularly mind which way we decide, but I'd like it to
be consistent, and I'm going to insist that if something is
Priority-Regression, it blocks a release.

Opinions are only sought from actual developers (i.e. the people
who will be fixing such bugs).  If you're an interested user or
new contributor, then although I would generally encourage you to
join the discussion, please don't get involved in this one.

Cheers,
- Graham