Bandera de escape

Bandera de escape
 

I'm looking for an English translation of the following expression:
'Bandera de escape'

It was taken from the paragraph below, which is from a text about illegal immigrants:
"Los menores viajan por semanas desde El Salvador, Guatemala y Honduras, con la pobreza y violencia como sus banderas de escape. Si son capturados por la patrulla fronteriza estadounidense, son procesados al interior del país y luego pasan a manos de la Ofi cina de Reasentamiento de Refugiados del epartamento de Salud."


Many thanks in advance.

reasons to seek refuge in foreign states. (reasons to escape to foreign banners)

I agree with Poli, with only a slight nuance: The use of the word "bandera" suggests that even if those weren't the real reasons why they're being displaced, that's what they'll say when the border patrol will find them. Like that, they'll have a chance to stay, instead of being deported right away.
Those are the reasons why they seek refuge anyway, but the use of a "bandera" is like wearing a banner all along telling to anyone they're escaping life-threatening conditions back at home.

Many thanks guys, much appreciated.