Half of the people who posted here sound like rescue has no CD at all.
You can misuse any skill and it will somehow harm the group:
using CDs at the wrong time and when it's not needed causing you to lose dps (especially bad on dps checks);
using wrong heals (like single target heals instead of group heals) and let your group die;
etc.
From my personal in game experience, there's nothing wrong with letting a random healer to rescue you. It could be a missclick, healer is about to cast AOE heal and you're too far, you're about to get hit and they don't know if you can take it.
And of course if you are being constantly rescued on CD, you ask them to stop and they still continue - report them, it is harassment.
Rescue is a very useful skill, it helps a lot when you know how and when to use it. Nothing bad with being rescued when the healer had no bad intent behind it.