I think we have determined that its not a Hampton standard to allow a tip jar.
I think these things are rogue and am surprised the local management is allowing it. Clearly the corporate standard does not.
I try to be very discrete when I give out the gift cards as I wouldn't want them to get in trouble for accepting tips. I think the standard also doesn't 'allow' making homemade chocolate chip cookies and giving them to your guests, so I accept them on the download.