I'd like to see a notification alert when adding a contact if they are over allocated somewhere else. Currently, the heatmap at the side only shows that a resource is over allocated, yet still allows you to schedule. There should be some sort of stop mechanism so this does not occur.
Having an alert that the contact we are trying to schedule is already allocated or over allocated, and for it to include all the locations and the owner of the sheet, would be extremely helpful. It would also be nice if the notification provided an option to send an email or comment to the other sheet owners that the contact is needed during the same time, and it would generate a conversation to discuss schedule changes, rather than just over allocating them.