I'm planning a trip to Europe next summer and found AP availability from YVR to ZRH with a layer over in FRA, with partner airlines (LH and LX) on a fixed award (70,000 in J).

What is odd, is that when I search YVR-FRA on the same date, the LH flight does not show up, its only when the final destination is ZRH does it show.

Since my preferred destination is FRA, could I book the YVR-FRA-ZRH and simply not show up for the last leg to Zurich? I plan to book a separate flight from FRA to FCO or MXP.

Would there be any penalty or downside to this?