The only real risks are an aircraft substitution and an INOP F seat. IRROPS involving cancellation is always a problem because rebooking may take time, but that can't be helped. In that case as an award ticket with no status, you would likely be the first to get the boot.
But, the risk is very slight and FT simply magnifies the issue because you won't find many people who bother to post when all that happens is that they check-in, board, fly, deplane and head off to do whatever it is and don't have an issue.