I do find it amusing when sceptics constantly bandy around that phrase - "No evidence of an abduction!" - like they think this is some brilliant point they are making. It isn't, and what's funnier is that most of them don't even realise how weak their point actually is.
First of all, the statement itself is untrue. There IS evidence of an abduction. They are just choosing to believe that the people providing the supporting accounts of what was observed are all lying. The sceptics proclaim this as a "given", despite there being absolutely no proof to back the assertion up.
On the secondary count, the phrase offers a flawed promise. As much as some people will claim "I'm only pointing it out", the connotation of there being "no evidence" is deliberate. It is intended to imply that the prospect of an abduction taking place is therefore vastly dimished from what it otherwise should/would be when an abduction genuinely occurs. But the reality is, unless a witness actually sees an abduction taking place, there is rarely any "evidence" that a person has been abducted. By it's very nature, it's one of those crimes that leaves little evidential trace.
Someone is there one minute, then they are not. How can you "prove" they've been adbucted, if nobody saw it happen? The victim is not there to give an account of what happened to them, so what are you left with to find in terms of "evidence" of an abduction?
I'll open the question up to any sceptic who is willing to offer up their thoughts. "IF" Madeleine WAS abducted from 5A by someone like CB, what other evidence would you "expect" to have been found to indicate this is indeed what happened to her?