Desperate people will try anything.
At the very worst Palace may get fined if it's proven they gained access through nefarious means but for Cardiff to even try and suggest that had any role at all in their abject defeat would be ridicolous. If points were deducted or the match result voided (a really unlikely possiblity) then it would be a complete travesty and Palace should be prepared to take it to the courts. It's hardly like Cardiff have the squad or the need to rotate making their lineup particuarily suprising, nor did Palace have much time (24 hours at max) to prepare something against that lineup.