If they are hidden, of course not. But it also depends on the job they are applying for. For a sales or business man, they wouldn't be so welcome. Yet applying for construction or as a mechanic, they will do just fine. Mainly the difference is that in the latter job, they don't appeal to other people on a daily basis. Still, if the tattoo is hidden, of course they can get a job that focuses on their other skills instead of the ink on their skin.
Love the picture by the way.