For the language aficionados among us (I hope many people :-) ): "fæng" is related to "fange", meaning "to catch".
The vowel mutation a -> æ also takes place in German: fangen (verb) -> Gefängnis (noun), where ä is similar to æ.
Is that some kind of idiom in either Danish or English ?
Det er ikke på engelsk. Jeg ved ikke, om det er på dansk.
Not knowing the Danish legal system, do they note the distinction between a jail and a prison?
not really? We have "arresthus" which is a small lokal prison, that primarily house detainees who are awating trial
You've essentially described a jail. :)
Is it considered proper grammar to start a sentence with a conjunction?
In english, in the past - no, but nowadays - yes, it's OK
How would you say that without a conjunction at the beginning?
Is this like "It is what it is?"
I.e., tautological statement is tautological?
(Tautologisk erklæring er tautologisk.)
It is more to underline this: despite a humane treatment, availability of tv, library, etc., you cannot get out. The key disadvantage...