@Judy174
Hmmmm.....as someone who is highly dependent on Amazon international shipping, I really understand your guests. BUT as a fellow host I completely agree that your concerns are valid.
First, I think if I were the host, I'd consider how long those guests are staying. If they are staying for a week or longer, I would very very reluctantly say they can have packages delivered ONLY if they time the orders (or use prime shipping) so the packages are delivered during their stay. Tell them clearly you will not recieve/store/hold on to packages for them before or after their stay - anything that comes that is not yours will continue to sit out on the curb or you will refuse to accept (wrong address). No exceptions. And if you are inconvenienced because of their package deliveries in any way whatsoever, you will ask them to leave immediately with no refund. If they agree to these terms, then as long as they are present to recieve deliveries, I'd say order away.
If they are staying with you 2~3 nights and want you to store packages for several weeks - don't have to think about it. This is a flat out NO.