...mainly because when I put 

changes interactive

it in my ~/.darcs/default file, then there is no way to selectively 
unset this option. I needed this to fix darcs-monitor which fails 
if --interactive is the default for darcs changes, and I could not fix 
it because of the missing --no-... switch.

patch540 solves the issue but it might be pointless.  Does -a do what
you want? Please see http://bugs.darcs.net/patch540

Yes, -a works as expected. It just did not occur to me that it might.
Might make sense to add --no-interactive as an alias to make it more
obvious...

I don't know if this is a good idea, maybe improve the doc instead?

Anyway, changing to whishlist.

Argh! Caught between two principles:

* keep flags symmetrical --foo should have a --no-foo
* avoid proliferation -- "what's the difference between --all and --no-
interactive", "oh they're the same"

I think we can pull out a third (meta?)principle here: when in doubt, be 
conservative about changing the UI (change has a cost, could end up 
making things worse in unexpected ways; only change if you have a 
reasonably convincing argument that it would improve the UI)

With apologies for my lack of courage, shall we not make a decision on 
this until issue1457 is resolved?

Ferenc (wferi) ran into the same issue.  This sounds like a good 
ProbablyEasy bug.  Why wait for the flag overhaul (which in all 
likelihood, won't happen till Darcs 3?)