[KingJami (OP)]

Hey, is this really possible?

If yes then should I avoid using mobile phones outside or even in-car?
Seems to me that there should be some danger signs on phones then...

[BenV]

I've changed your subject to a question, in line with forum policy.

[graham.d]

I would assume that, when transmitting, the radio waves would reduce the breakdown voltage of the surrounding air. With the limited power of a mobile phone I would not expect this to be very significant, but it could increase the chance of a lightning strike, if only by a small amount. Perhaps it is equivalent to being a few feet taller. It would be worse if a long way from the cellsite and therefore using the highest power transmission from your handset.