I meaned a bit different indent cases.
1 Allowing to eat first space
>foo
> bar
2 Floating spaces between nested bq
>> foo
> > bar
Case from your example is not a problem at all - blockquote content has fixed shift for all lines. In my example content shift is drifting on each line.
Are there any cases, when such drifting is really needed? IMHO, visually it looks ugly. It seems, that if user starts using one style, he will keep it the same on all bq lines