>>48357552>>48357619It's logical to infer that the Pokémon are imported because The Safari Zone is a man-made environment - while a preserve for rare Pokémon, its primary function is to house an organized catching game. Balanced catching games require an abundance of common, uninteresting encounters and rare, valuable encounters. In Kanto's Safari Zone, it makes sense for the catching game's common encounters such as the Nidoran, Venonat, and Doduo families can also be commonly found in Fuchsia City's neighboring routes.
An NPC states that certain Pokémon can only be found there. The game's encounter tables' prove this to be true. The zoo in front of the Safari Zone, exhibiting Pokémon that cannot be found neighboring Fuchsia City (Voltorb and Slowpoke being found in Route 10 and Seafoam Islands) or at all (Lapras and Omanyte(?), with Chansey and Kanghaskhan only in the Safari Zone) is evidence of importing.
How else are Scyther, Pinser, etc. only there exclusively when it's the bug-catching contest? Scyther most likely isn't endangered (it can be found plentifully in Sinnoh's Route 210), but is a rare Pokemon to Kanto/Johto. Not exactly a stretch considering Syther and Pinser were being sold as prizes in Celadon's Game Corner.
This is all based off evidence provided explicitly from the game. Lapras' Pokédex entries provide its history of being endangered. However, Scyther and the like have no mention of endangerment in the game. Why assume that Scyther can be found elsewhere if the player cannot actually find it?