Why can I use named pipes to connect to SQL Server even if it's been disabled?
Check the SQL Server error log for the named pipes provider messages.  With named pipes enabled, you should see messages like those below and be able to connect both locally and remotely over named pipes:

Server local connection provider is ready to accept connection on (named pipe)
Server named pipe provider is ready to accept connection on (named pipe)

With named pipes disabled, you should see only local connection provider message(s).  You'll still be able to connect locally via named pipes (over shared memory) but not remotely via named pipes.