autovon - 155 mile rule on CB is to prevent RFI interference with AM-FM broadcast and other frequency, its why 1K Linear Amps are banned, for this reason, Its completely legal to DX CB but not Transmit. screws with other Homes in your Area, Part 15 Radios, Broadcast Radio , and VHF Air / Marine.
The ONLY portions Blocked in scanners are the Analog Cellular portions 800/900 MHz. everything else is FAIR game, but Scanner makers use CHEAP receivers that have Missing gaps in Coverage to save money. Professional Scanners like the ICOM R30 and AOR DV-10 don't have ANY missing gaps in coverage , except for the Cellular Portion, per FCC Mandate. and Scanners also have Narrow Coverage compared to the ICOM, 100 Khz - 3304 Mhz. scanners cover only Above 26 MHz - 1300 MHz , but with GAPS in coverage. which makes them barely useable for HAMS and People waning SW and HF reception.
Pre Ban , I bought a AOR 1000 scanner, it can scan Analog Cellular as well as Cordless Telephone, CAR Phones, Wireless Intercom, Baby Monitors and Wireless Doorbells, garage openers.