Deut 18 is a good one to show what is the requirement of being a false prophet particular verse 18.
Deuteronomy 18:18-20 (New International Version)
18 I will raise up for them a prophet like you from among their brothers; I will put my words in his mouth, and he will tell them everything I command him. 19 If anyone does not listen to my words that the prophet speaks in my name, I myself will call him to account. 20 But a prophet who presumes to speak in my name anything I have notcommanded him to say, or a prophet who speaks in the name of other gods, must be put to death."
This is clear concise and simple. It is describing how we recognise an INSPIRED prophet that has heard words DIRECTLY from God and a false one that CLAIMS to have heard words from God. This is a lot more than just saying something "in the name of God" basically representing them but actually claiming to say words directly from God that he hasn't commanded them to say! Basically saying you are inspired of God.
Hannaniah broke this rule completely by saying he heard from God directly the words he spoke and he died for it. So it's clear To be a false prophet you have to Claim to get the word of God from God himself and if those are not what God has commanded you to say directly that is when you get condemned.
The principle for being an inspired prophet able to do prophecy is in the greek scriptures too.
2 Peter 1:21 (New International Version)
21 For prophecy never had its origin in the will of man, but men spoke from God as they were carried along by the Holy Spirit.
This is what is meant by being “God-breathed.” inspired.
And as Deut 18 shows if you claimed this becoming a false prophet by lying the penalty was death.
The deciding factor was someone saying they spoke words DIRECTLY from God himself.
Witnesses have never claimed this!
The Watchtower does not claim to be inspired in its utterances, nor
is it dogmatic. It invites careful and critical examination of its contents in
the light of the Scriptures.
"Name and Purpose of the Watchtower," The Watchtower, 15 August 1950, 262-263
In this regard, however, it must be observed that this “faithful and
discreet slave” was never inspired, never perfect. Those writings by certain
members of the “slave” class that came to form the Christian part of God’s Word
were inspired and infallible, but that is not true of other writings since.
Things published were not perfect in the days of Charles Taze Russell, first
president of the Watch Tower Bible and Tract Society; nor were they perfect in
the days of J. F. Rutherford, the succeeding president. The increasing light on
God’s Word as well as the facts of history have repeatedly required that
adjustments of one kind or another be made down to the very present time.
The Watchtower, 1 March 1979, page 23-24.
I could have picked many more quotes and practically from every decade also reiterating that they are not Inspired.
You can try and bring out badly phrased wording from watchtowers or awakes but all that shows is that they ARE imperfect and not inspired like they have ALWAYS said.
The point about false prophets and hananiah Is they claimed to be speaking the Actual words of God himself.
that doesn't stop us be confident in our speach giving credit to God as Gods people on earth.
1 Peter 4:11
If anyone speaks, he should do it as one speaking the very words of God. If anyone serves, he should do it with the strength God provides, so that in all things God may be praised through Jesus Christ. To him be the glory and the power for ever and ever. Amen.
The line is drawn when you say you ARE inspired and can speak words from God himself and incidently any other Gods. (this would include Jesus if you think Jesus is God and claim to get words from him).
an example for you to think about is Papal infallibility.
Papal infallibility is the dogma in Roman Catholic theology that, by action of the Holy Spirit, the Pope is preserved from even the possibility of error [ 1 ] when he solemnly declares or promulgates to the universal Church a dogmatic teaching on faith or morals as being contained in divine revelation,