Ok I'll bite.
Let's say for a moment that Jehovah's Witnesses are right, and that the NT autographs (the originals) contained the Tetragrammaton.
Let's say that the NT writers ALWAYS wrote "Jehovah" in Greek (Iexoba, as the Witnesses spell it currently) when they quoted the Hebrew Scriptures, whether they quoted from the Hebrew version or the Septuagint, and Jehovah's Name appeared on the quote. Let's say that the original Septuagint ALWAYS had Iexoba whenever they were referring to Jehovah.
Then we have that the original Septuagint said in Psalms 101:26-28 the following:
"At the beginning it was you, O Jehovah, who founded the earth, and the heavens are works of your hands. They will perish, but you will endure, and they will all become old like a garment. Like clothing you will change them, and they will be changed. But you are the same, and your years will not fail."
Then, appropriately, Hebrews 1:10-12 would read
10 And: “At the beginning, O Jehovah, you laid the foundations of the earth, and the heavens are the works of your hands. 11 They will perish, but you will remain; and just like a garment, they will all wear out, 12 and you will wrap them up just as a cloak, as a garment, and they will be changed. But you are the same, and your years will never come to an end.”
What about this other scripture?
Psalms 32:9 in the "original" Septuagint would have read
O taste, and see that Jehovah is kind, happy the man who hopes in Him.
And therefore, the "original" NT would have HAD to have said
(1 Peter 2:3, 4) 3 provided you have tasted that Jehovah is kind. 4 As you come to Him, a living stone rejected by men but chosen, precious to God,
Oops!
What have we done? Says the Watchtower.
We have called the Son Jehovah!!
The New World Translation suddenly here backpedals really really hard on their statement that the Septuagint contained "Jehovah" and that the NT writers had NO CHOICE but to respect the name and put it whenever they quoted from the Hebrew Scriptures where the name was found!
Actually, this is what they do currently!
They do NOT follow their own rule, their own statement, with regards to "Jehovah" in the Septuagint and/or the New Testament when it does not suit their needs/preconceived notions!
Hebrews 1:10 and 1 Peter 2:3 in the New World Translation contain "Lord", NOT "Jehovah", because it would put them in an awkward position, theologically speaking.
Let's go a bit further.
Let's say that the Peshitta is a closer version to the original than the Greek New Testament.
Let's say that every time the Peshitta says "MarYah", it means "The Lord Jehovah", as it does throughout the entire Old Testament.
Then we would have MANUSCRIPT EVIDENCE from the 6th century that Luke 2:11 reads
(Luke 2:11) 11 For today there was born to you in David’s city a savior, who is Christ The Lord Jehovah.
If Jehovah's Witnesses are right, then let's pack our bags and call it a day. Jesus is Jehovah Himself!
If Jehovah's Witnesses are wrong (my opinion), then let's pack our bags and call it a day. They changed the Bible to suit their needs. Heck, every single Bible translator has in some way modified the Bible, so the Bible is not trustworthy, and therefore the Witnesses and every Bible-based religion is false. Let's all be atheists!
Check. Mate.