[Monotone-devel] Why does pull require -k?

[Boris]

After synchronizing my monotone database with another I can use 'mtn sync' 
and 'mtn push' just like that (as monotone remembers everything from the 
first sync). However 'mtn pull' tells me it does an anonymous pull. I have 
to use -k to specify which key I want to use. Is this is a bug? I wonder as 
I don't find anything in the documentation that I need to use -k for pull 
all the time while sync and push remember?

Boris