'#' in usernames with scp

[Christopher Key]

Hello,

Some hosting companies insist on having usernames of the form
user#account(@example.com).  The ssh client is quite happy with such
usernames, but scp fails with 'invalid user name'.  Looking at the
source code, scp rejects ' " ` # and ' ', whereas ssh apparently
enforces no such restriction.

My question is twofold:

Firstly, why do ssh and scp behave differently?  If the restricted
characters are eitther dangerous or outside spec, why does ssh permit
them?  If not, why is scp rejecting them?

Secondly, is there any chance of getting this changed to be consistent? 
I'd obviously prefer that scp accepted '#' characters so that I the
standard source works for me, although if there's a good reason for
rejecting some characters, should ssh not be updated to reject them too?


Christopher Key