6.4 and accessibility

It seems possible to rephrase this part of 6.4.4 to not be just visual:

"For visual user agents, these interactions MUST be presented in a way 
that makes it impossible for the user to view or interact with the 
destination web site that caused the danger situation to occur."

could instead be:
These interactions MUST be presented in a way that makes it impossible for 
the user go to or interact with the destination web site that caused the 
danger situation to occur.

For the header recommendations, I could use a bit more context (I'm only 
about two pages into Serge et al's paper; I'm hoping to finish it on the 
trip out to the RSA conference): 

"For user agents with a visual user interface, headings of these warnings 
MUST include words meaning "caution" or "warning". The headings of these 
warnings MUST be the locus of attention."

Why the headings? Is it _just_ about locus of attention? Are there other 
things about the headings that make them special?