When using the room finder to book a meeting longer than 24 hours or outside of work hours it doesn't suggest any times due to multiple reasons. If not using the room finder, the scheduling of a resource will allow the user to book the resource even though the resource is already booked during this time, and not until after booking the meeting the resource will send an e-mail informing the user that the booking has been rejected.
We're working with a customer that wants to book a room (a car in this case) for multiple days including outside of work hours. Using the room finder is the most convenient way to book in the calendar because it won't allow you to double book a room. As mentioned above if a user books a resource manually it's not certain that the room was free for that time, unless you manually check beforehand, or when you get a response letting you know the booking has been confirmed.
The customer has a shared calendar. The current setup works as follows: The user creates a new meeting in his/her own calendar and books a resource (conference room or car). The resource forwards the invitation to the shared calendar, so that the meeting shows up in the users own calendar, the resource calendar, and the shared calendar. If booking a resource a full day (by choosing all day event) the shared calendar automatically accepts the invitation. Also if you choose to book it during work hours. However if you book the room over the course of multiple days between two specific times, the shared calendar does not auto accept the invitation. It does however if you choose all day event for multiple days. Canceling a meeting in the users calendar doesn't completely remove the meeting from the shared calendar, although it's been set up to remove canceled meetings.