YVR FRA PRG (off in PRAG) VIE
Want to book this as award travel. If I do not make it a RT but book the return as a one way, I don't think UA can do much about it. Carry on only. Never done this before, but UA's connection are in most cases lousy unless you are ready to shell out 200K+ Just looking for negative advice as to why I should not do this.
The primary reason not to do this would be that UA — well, LH, since this appears to be an LH itinerary — has no particular obligation to send you to PRG. They can put you on FRA-VIE instead — and since this trip is covered by EC.261, they very well might try to do so if FRA-PRG is cancelled or delayed.
In theory, UA could take much harsher action, but I’ve never heard of them doing so for a one-off.