Recommended? Yes.
Required? Not necessarily.
Different lengths of wire feeders can cause individual digital commands to arrive at the track at different times, resulting in digital echoes racing about on your track and possibly causing unexpected behavior of locomotives. Placing third-rail insulators between feeders alleviates this avenue of chaos. The star wiring method was intended to minimize signal duplication by having all track feeders (and thus control signal paths) as close to being the same length as possible.
I added a feeder to the far end of my 11x17' test-track loop, and sometimes if I hit the "two horn blasts" softkey, the locomotive will give two horn blasts--twice. Placing an insulating pin between the two connection points would solve that particular issue (but it hasn't become an operational problem so far)
---PCJ
