I was going to comment along those lines, we are a small company with multiple locations and more than one in our metro area, if someone calls the wrong location (always us, we are the original, option 1 on the tollfree number) looking for an invoice to be emailed, we have to switch over to each other property until we find them. We have some guests who stay at each of our local properties based on availability. Or we have guests who will turn up at the wrong location, it would be so helpful to just pull up their name and see, you are booked at our location on 12th street, let me give you directions on how to get there.

In my opinion it is a basic functionality for at least the multi property users to being able to search for a guest and find his reservations no matter of the property you are currently logged into.
Seeing the guest history or future reservations should be visible across all properties with shared Guest and company profiles.