Some destinations don't have 100s. Some destinations don't have doubles. Some destinations don't have extra small or double extra large wet suites. Some destinations don't have a lot of things.
That's why people have to plan their trips. If you need to bring a computer, bring one. My LDS will rent gear for use anywhere in the world - we have a very competitive weekly rate. Which means our students can take the computer they were trained on with them.
OK, makes sense......Unless your student moves to a location that either doesnt have a dive shop, or doesnt rent the same computer that you do.