Access denied when piping to :Null

It's quite a common thing in my batch files (yes, .BAT is still alive) to limit the verbosity of the output displayed to the user. It's a 'seeing-the-wood-for-the-trees' thing: I don't want to have the user waide through screens of output to know that a CACLS worked ok (and potentially miss something important)

So I quieten things down by piping to null:

aspnet_setreg -k:SOFTWARE\MyCompany\MyApp -u:"%username%" -p:"%password%" >:null

...and listen for ERRORLEVEL instead.

But recently I discovered that this fails with Access Denied if you don't have write permissions to the current directory (yes, you need write permissions to write to :null. Just don't ask). Not only that, but the whole statement fails, not just the piping bit.

So these days I pipe to %temp%\null instead.