No entry for an instructor's availability should mean they are unavailable that day.

Preface: 

Based on the interface design, I'm fairly certain this is a bug, and it should work as expected.  

But when I contacted the support team about it, I was told differently and was asked to add an entry to the idea board.

Problem Description:

In this example, we have two instructors with their availability set as shown here:

Simple. Easy enough for any user to understand how to do, and adjust when necessary. Right?

And because nothing is listed for Instructor A on Mondays, one would naturally assume Book-A-Pro should show that instructor as unavailable on Mondays.

Otherwise, what would be the point of identifying "Availability Intervals"?  Who works seven days a week, from open to close?

This only makes sense as a tool to specify the times the instructor is available each day of the week.  

The assumption that blank means unavailable is in no way a stretch.

However, this is not the case, as we see when we view the Book-A-Pro scheduler in the member portal:

When I asked about this, the support team suggested that the only way to get this to work is to use the Create Unavailable Time tool.

Disclaimer: 

I'm the club's IT consultant and the primary person responsible for configuring CR and training users.  

Yes, I'm fully aware of how these tools work.  

What follows demonstrates what our instructors and other (sub)admins must navigate to do what the support team suggested.  And that assumes they don't just give up and call me to do this for them.

Okay.  Let's try this...  We want it to be generic, occurring on the days of the week that the instructor is not available.  So, something like this:

Nope.

Okay...  I'm not sure how we'll handle next year, but let's try December 31st.

I should have seen that coming....  Let's have it start January 1st.

Start of the day to end of the day...  Fine.  That works.

But what about next year?  

Now, I or they have to remember to go back in at the end of every year and update this for every instructor.  

What if they later set an unavailability block because they're going on vacation?

Now, CR will throw an error because that block overlaps this one.

The list goes on...

Conclusion:

There is currently no intuitive method for instructors or other (sub)admins to adjust instructor availability (or rather unavailability) within Court Reserve.

By all appearances, the Instructor Availability tool may or may not have previously worked as assumed at the top of the problem description.

At the very least, that is the most obvious place for end users (i.e., instructors, not the club's IT guru) to look for where to set their hours.

By contrast, the prescribed method for setting unavailable times is a great solution for when the instructor needs to block off time with set start and end dates.  (ex. vacation)

But it is entirely too limited in its capabilities for setting general "unavailability", the need for which is counterintuitive to the point of being absurd.

Thank you for attending my TED Talk.