Group 1 - The article highlights the illegal installation of signal jammers by individuals and organizations near airports, high-speed rail, and subways, which disrupts wireless communication and poses a threat to public safety [1][3] - A case was reported where a breeding farm near an airport installed a signal jammer to prevent competitors from using drones, which inadvertently interfered with critical aviation signals, endangering civil aviation safety [1] - Another incident involved a car pawn shop that installed multiple signal jammers to block GPS signals of collateral vehicles, which also affected high-speed rail and subway communication systems [3] Group 2 - The national security agency emphasizes that signal jammers are illegal and their unauthorized purchase and installation can lead to legal consequences [5] - Citizens are encouraged to report any suspicious activities related to signal jammers through designated channels [5]

Group 1 - The article highlights the illegal installation of signal jammers by individuals and organizations near airports and railways, which poses a significant threat to civil aviation safety and disrupts public transportation operations [1][2]. - A specific case is reported where a breeding farm installed a signal jammer to prevent competitors from using drones, inadvertently interfering with critical aviation signals, leading to safety hazards for civil aviation [2][4]. - Another incident involved a car pawn shop that installed jammers to block GPS signals, which also affected high-speed rail and subway communications, prompting legal actions against the responsible parties [4][5]. Group 2 - The National Security Agency emphasizes that signal jammers are illegal and warns the public against their purchase and installation, urging citizens to report any suspicious activities [7][8].