Their are many who I feel have already taken up this role.
The problem is the same as it was back then.
Gitting people to listen. And even more to believe you.
It is the same as it was in Noah's time.
People will either think you are just a kookie exteremist. Or that God will save them no matter what they do.
Untill its to late.
People have a tendency to forget that even tho God is a god of mercy.
He is also a god of justice.
He will forgive, But if someone goes to Him, telling Him about how someone has wronged that person. God has to see that the wrong was made right.
And that the people who ignore the chance to make things right, will be the same people who feel his wrath.
And even tho the watchman tells them of their doom. Their hearts will be made cold.
And they will not act on the things that are obivious to others.
In other words the watchmans job will have no validity to the people who have not kept themselves open to God's ways.
Just like if you stop listening to your parents, they will get tired of telling you. And let you go and make your own mistakes.
Just an opinion. Not that I have any special insight.

To 'Only onus"....

It is the watchmans job to sound the alarm..............

Not to make ignorant mankind actually "listen" in mass.

"many are called few are chosen".............billions will die anyway........

But still God commands the watchman to sound the alarm......