Should I leave a reference?

Let's break the problem down and make it simpler. First, we'll make a couple of assumptions for the purposes of illustration:

• They've got a dozen references already - all recommended with no late cancellations or no-shows - so their references headline says: has 12 references; 12 positive, 0 negative, 0 late cancellation and 0 no-show.
  
  
• They cancelled a shoot with you just a couple of days in advance.

So your options are:

1. Don't leave a reference at all. Their headline will stay unchanged. No-one will be any the wiser.
   
   
2. Leave a Cancelled with less than 72 hours notice reference. Their headline will change to: has 13 references; 12 positive, 0 negative, 1 late cancellation and 0 no-show. They then have to explain themselves to those who care to ask.

Just imagine

They might make a habit of cancelling in the same fashion or engaging in similar inappropriate behaviours. Imagine further if other people take the view about not leaving a reference.

For the sake of illustration, let's say it happened to 5 more people. Where would that leave me if I noticed them and wanted to book a shoot?

Taking those options (from above) again:

1. Don't leave a reference at all. Their headline will still stay unchanged and will still say: has 12 references; 12 positive, 0 negative, 0 late cancellation and 0 no-show. 
   It'd leave me unaware of an important part of the picture. I would be potentially vulnerable to having it happen to me.
   
   
2. Leave a Cancelled with less than 72 hours notice reference. Their headline would say (if other members from the 5 previous shoots have also added the late cancellation references): has 18 references; 12 positive, 0 negative, 6 late cancellation and 0 no-show. 
   This would show up as a red flag. That's not to say that no-one will ever work with this person: strings of no-shows (or late cancellations) have occurred and then the person has turned themselves around successfully. But it'll avoid people getting into such a situation without prior warning. People looking to book a shoot with them will be far more likely to question the situation.

So in isolation your reference may not make much difference to that individual or to anyone else. However, it's when a pattern emerges that the difference will be seen.

In summary

So yes, in summary, please leave the appropriate reference, for the sake of your fellow creatives!