Quote - Are these programs rigged so you can only install on the that day?  What if down the road you want to re-install? SOL?

This is not possible since the site merely gives the opportunity for people to test the software. The prize for doing so means that you get to keep using the software till you uninstall it. However, if that happens you cannot reinstall it.
To be honest, it's worth keeping an eye on this site as useful software does tend to pop up regularly.