My view on the OPs question.
There are legal restrictions on use but unless anybody does anything reckless or stupid like impersonating Heathrow Tower I have never in 40 years heard of anybody being prosecuted for quietly listening out. There isn't any restriction on sales, otherwise Transair and Harry Medelssohn wouldn't sell them over the counter and by mail order.
I regularly transmit on my old IC-20 by standing next to the aeroplane and saying "Tower G-ABCD Radio Check handheld" If that's illegal so be it.