Regarding "How to Deal With Unhappy or Angry Guests" : MY RESPONSE
I do think #4 is a biggie (Acknowledge the situation - that You fell short in meeting the customer's expectations). They are on holiday after all, and may have needed something to go really smoothly for a reason.
Mgmt doesn't know the background of each person's situation . So while it 'may' be helpful to acknowledge a misstep (or even apologize), that won't solve it in every case.
Therefore, Mgmt has to train the personnel well - to be able to judge which instances call for something more - such as a Free spa day, or a free night's lodging, etc.
Some employees are better at diplomacy than others - I would think those are the individuals to reward, and give greater responsibilities.
The url which my reply is DIRECTED at is :
https://bookingteam.com/2017/07/28/how-to-deal-with-unhappy-or-angry-guests
In case any of you wish to #read more of the article/reference