Many states forbid the use of Radar detector/scramblers. So, if you live in a state, or plan to cross a state, that radar detectors are illegal, you too may consider concealing it.
That would be real fun to get pulled over with a concealed detector in one of those states: "Sir, you are going to have to remove that".
I vaguely remember this topic being discussed at least once or twice before, I wonder what I would find if I did a search...
In the US radar detectors are only banned in the state of Virginia and the District of Columbia, Washington D.C. Assume that they are banned almost everyplace in Canada.
Out of sight is not out of mind. Police have and use radar detector - detectors (RDDs) and they work really, really well, some able to sense radar detectors more than a mile away. There are some combination of radar detectors and RDDs that have limited detection range and other combinations that would allow RDD readings close to 2 miles away but these are not the average situation.
Scramblers are illegal in several states.
IMO, the only reason to hide a detector is in case you get pulled over, at this time it would be - ahem, discrete to have the RD out of sight. Strategically placed coats and helmets make great invisibility cloaks.