Refresher courses is an issue that always brings up a multitude of opinion. Really, it depends on two factors....
1. Dive Shop Policy. Many dive shops will have a set policy that dictates when a refresher course is warranted. This policy will take into account your experience/certification balanced against the length of time since you last dived. If you disagree with the policy of a certain shop, you can always ask around until you find a shop that won't be insistant. However, in my experience, those shops that are lax with refreshers tend to be lax about other safety issues.
2. Your personal comfort. Regardless of what a dive shop policy may state, you should always conduct a refresher if you feel that you will be more confident and relaxed for having taken it. As such, it doesn't matter whether you are going to an 'advanced' site or not - the purpose of the refresher is to make you safe and comfortable underwater. If you need it for an 'advanced' site, then you need it for a shallow site.
From my own personal experience, the demands of both these sites are entirely dependant on the depth you will be going to (deeper is better if you want to see sharks) and the prevaling weather conditions and visibility.
Some dive schools run OW dive 3/4 at those sites...because both allow diving within the 18m range....so don't be discouraged from the sites. But to get the most out of them....you want to be with a group that will be going to 30m....