[kbolino]

Strictly speaking, as with cargo/rustc, the Go module system and Go compiler are separate, and the latter can run without calling the former. There are various flags to tell the "go" command (which is a frontend to other tools) how to behave when modules are involved, e.g. so that it works well on airgapped networks and locked-down intranets or can be used safely with untrusted source. You can also still vendor modules to ensure they are locally available.