Venetian Blind Schema - effect on Xpath

Supposing I used  a Venetian Blind Schema to facilitate toggling
namespace exposure in my instances.

So now whether or not local elements need to be namespace qualified
depends on the setting of elementFormDefault.

Thats fine for schema validation but how does it affect any XPath's I
write if I were to toggle elementFormDefault?

Trying to understand this from a "this is actually what is going on"
perspective rather than just experimenting.