Isn't this the sort of thing that Paul was warning the church in Thessaloniki about? At the beginning of 2 Thessalonians 2.
It seems as if these kinds of rumours were going around even in the lifetime of the apostles.
I would also bear in mind how Jesus warned us of many false messiahs and false teachings.
He said the Gospel would be preached in all nations, before the end. They still had a long way to go in 70AD
He warned
23 Then if anyone says to you, ‘Look, here is the Christ!’ or ‘There he is!’ do not believe it. 24 For false christs and false prophets will arise and perform great signs and wonders, so as to lead astray, if possible, even the elect. 25 See, I have told you beforehand. 26 So, if they say to you, ‘Look, he is in the wilderness,’ do not go out. If they say, ‘Look, he is in the inner rooms,’ do not believe it. 27 For as the lightning comes from the east and shines as far as the west, so will be the coming of the Son of Man.
(Math 24 ESV)
When he comes there won't be any doubt. The whole world will witness it.
I think Preterists have that absurd notion that we are currently in the millennial reign.
1000 years of peace despite 2 world wars, The Armenian genocide, Bubonic plague, Islamic terrorism, Pol Pot, Idi Amin etc etc.