I don't know what kind of treadmill you ordered but I would love to see some of these "Internet Men" just throw together a Cybex or Precor treadmill. I guarantee you most of them couldn't even adjust the deck belt lol. If you got free installation, take advantage of it.
And I always tip anyone performing a service for me. Only time I usually don't tip is when the someone has already figured in "labor." ie body shop or mechanic