BR element and generated content

CSS2.1 default stylesheet defines <BR> element as

br:before       { content: "\A" }

If taken literally, this means


1)      Generated content is applicable to <BR>

2)      If a non-default stylesheet clears br:before it should not break line lines.

I am not sure these are intended consequences of this definition in the default stylesheet. Or are they?

Note that none of current browsers implement (2) and I believe only opera has generated content have any effect on <BR>.