Tsukerareru, kotozute o tanomu

1) From a spy story, about a target:

「俺らみたいな人間につけられても気付かないような素人だ。」

The つけられて mostly like means "to be followed" in this context, correct? I know "tsukeru" has many, many uses, but there really isn't an alternate one in this context, is there?

2) Further on:

「お前が囲い込んだ密偵とやらに言伝をたのまずこの作戦に出たのは何故だ。」

The 言伝をたのむ bit means "to leave a message (for the spy's bosses) with the spy," correct? ("You had the spy surrounded, but instead of using him to send a message, you went with this plan, why," etc. right? The object of に is the one with whom the message is left, not the one for whom the message is intended, correct?)

Thank you for any assistance.

- Yes, "tsukerareru" in this case means "to be followed," like by a private investigator/detective, etc. So it says: "he/she is a complete amateur who doesn't even notice that they were being followed by someone like us."

- "Why is it that you/they took this tactic instead of leaving a message with the spy you say you retained/captured?"

I can't quite tell what they mean by "kakoikomu" - whether they mean they physically surrounded and captured, or something else.

Thank you very much. Let me ask you: could the first sentence be a hypothetical? "If he were followed by someone like us, he wouldn't notice" etc.?

Yes, it could be a hypothetical. You can take AK's translation above and replace "doesn't" with "wouldn't" and it would still be correct (obviously the English would have a subtly different meaning, but in this case the Japanese can be either.) Context would usually indicate whether the person was actually followed and didn't notice, or if it's simply the speaker's judgement that they wouldn't notice were they followed.

Thank you both very much.

2)
That 囲い込んだ(囲う based) meanig is NOT "surrounded"
means just "hired/bought by money(or promised keeping good life)" as unofficial(out of subordinate person).
http://dictionary.goo.ne.jp/jn/39836/meaning/m0u/
→ 3. 人に知られないようにして世話をする。

"やら" means "no exact/not sure" so angry guy(boss?/saying "Why?") doesn't have spy's details anything just heard/reported such spy exist.

密偵(spy who joined/close to enemy/terget group) is often sacrificed(killed together)
by wrong/overbearing operation for making more exciting story.
But in that case no sure spy died or not,
so, that spy's usage may overed by that stupid operation.