Typically the salary being offered by these outfits is WAY below the salary one would expect for an experienced professional.
Well, during my expat days, the Ozmates confided "Give a Brit a uniform and he'll fly for nothing!"
And the Brits said "Hire two Ozzie's and they'll form a labour union!"
Of course, hire an American and he'll quit when a job driving the lav truck opens up back home...