AFAIK restricted accounts can't install apps. I might be mistaken since I don't use that feature but I have just created one such account out of curiosity :

AFAIK restricted accounts can't install apps. I might be mistaken since I don't use that feature but I have just created one such account out of curiosity : - the admin can decide which apps are useable from the restricted profile. - it seems that the restricted account can't install additional apps.