Before we go down the path of debating "listen first" or not. I will remind folks that most of the argument has been stated before. Aside from the legalities of the issue, there are camps that strongly advocate that every hams should also listen first and not transmit if the frequency is busy, and those that feel some modes have such short initial identifying bursts that listening first is not necessary , and perhaps antiquated. I think we should acknowledge both viewpoints, without dragging the issue on and on. What I do feel needs pointing out is that if you take the first position, that one should always check a frequency and inquire if it is free, logical would dictate that this applies to all aspects of hams radio including contests. A contester that calls CQ Contest without QRL is as "guilty" as an ALE or Packet station. Since I am a contester, I might argue that although the frequency is crowed, I think my signal can fit next to others without undue QRM. That might not be that much different than a Propnet station that fires up 32 hz away from me. I may think it annoying but they might feel I should be able to operate with a close neighbour.
Feel free to share your opinion on the matter but do so with respect for other opinions. In the scheme of things , whether one believes in "QRL first" or not, does not make the person with contrary views in to a evil dastardly person. We just differ. Andy K3UK