Space characters tell ULib in many instances that whatever comes after the space is a new parameter to the command being run. Some things are written in a way that spaces would be read correctly and you wouldn't notice until you try to do something like set permissions to groups, when you will notice.
It's just good practice to not use spaces in any form of variable or grouping naming convention. Underscores are a much more widely acceptable alternative. If you are coding and you need to display the name of something and want to use spaces, you can always do a simple string.gsub.
print("this is my test_group")
print ("this is my " .. string.gsub( "test_group", "_", " " ) )
would show as ("this is my test group")
