The first part seems to be the case - I just tried signing up with two different names but the same email address, one a couple of minutes after the other and they both went through. I also tried signing up with a foreign email address and that also went through and I received the email link to click; however, to be fair, the qualifying box to tick states that one must be either a British Citizen or a UK resident. I suppose this makes the petition about as as reliable as the Vote Leave campaign and only slightly less of a scam.Just to add some context, All the leavers were signing it on twitter under false names and multiple times with the same email address just to see how secure it was for the laugh... 80% are from overseas too, The whole petition has become a farce.
Secondly, The petition is to get MP's to "consider it for debate in parliament" Have they not been debating it for the last 2.5 years ??
It does seem to be a waste of time in the first place as the end result of the petition is a foregone conclusion: another pointless debate.