Perhaps one should look at Jesus's own words on the subject ( at least according to the Bible:

Mat 24:23 Then if any man shall say unto you, Lo, here [is] Christ, or there; believe [it] not.

Mat 24:24 For there shall arise false Christs, and false prophets, and shall shew great signs and wonders; insomuch that, if [it were] possible, they shall deceive the very elect.

Mat 24:25 Behold, I have told you before.

Mat 24:26 Wherefore if they shall say unto you, Behold, he is in the desert; go not forth: behold, [he is] in the secret chambers; believe [it] not.

Mat 24:27 For as the lightning cometh out of the east, and shineth even unto the west; so shall also the coming of the Son of man be.