I was all set on getting comfort access on my M140i but after hearing about this didn't spec it.
Haven't tried with the 1 but our 5 won't let you drive away without the key even if the engine is still running.
This article explains how they do it with easily accessible tech.
http://www.dailymail.co.uk/news/article-4427902/High-tech-radio-trick-used-steal-range-cars.html