Interestingly enough the publisher has pulled the original sign in app from the play store and replaced it with a new app with a similar name... My guess is they needed to as the old app was getting absolutely hammered with 1 star reviews. The tracking is really invasive. This is what it says about its access on the phone.
Attachment 522633
See hears the thing also. If they need people to sign into a job site, just provide a website where you enter your details... I might grab a really old phone that won't install the app and just play dumb and say it won't work.