@MENUMA432 In us there are devices nicknamed stingrays that intercept all cell or wireless data in an area and monitor activity.
However, here in Japan, the act of intercepting and decrypting other people's communications without permission using an IMSI catcher is prohibited by the Unauthorized Computer Access Act, and you could be subject to criminal penalties... (^.^;)
@MENUMA432 It is very similar here, only official agents are allowed to use such devices. While I don't know of any laws specifically banning them, consumer jammers are sold online, and I'm sure a charge of interference with communications could be used if someone was causing trouble and got caught.
@MENUMA432 As well as jammers like the one you encountered