icloud spam filtering

I have what I hope is a simple question:

I get a fair amount of spam in my .me account. I don't know where it comes from as I'm pretty xenophobic with my address. No groups, no one has it, separate email for signing up to things like facebook, etc. But I still get some.

Apple's recommendation is that when a spam arrives you simply mark it as junk. That's fine, but they also say that the mere act of opening a spam can trigger a script that allows the sender to determine that it arrived at an active, monitored account.

Thing is, in order to mark something as junk mail, I need to select it, and it then opens to the right and gives me the option to mark it.

My question is, is the act of clicking on a mail header to allow me to mark it as junk enough to send a read receipt back to the sender? If so, that seems pretty unhelpful. Is there some way to select a message and mark it spam before it opens to the right of the list of received messages?

Thanks, all...