The Smiths must still have the Hufflepuff Cup

[bridge13219]

No: HPFGUIDX 156522

 > Carol responds:
> I don't see that at all. Tom would simply take the cup, turn it into 
a
> Horcrux somewhere far from Hepzibah's house where he wouldn't be
> caught, and hide it, as he apparently did with the locket at roughly
> the same time and the ring somewhat earlier. Having murdered to 
obtain
> the cup, do you really think he'd return it to the family it
> rightfully belonged to or turn it into a Horcrux and leave it there
> for them to find? <snip>

bridge13219:
Maybe Tom turned the cup into a horcrux with Hepzibah's murder, and 
had Hokey hide it somewhere else.  Hide it in plain site (sort of).  
If it was such a valuable and special family heirloom, they're not 
likely to treat it carelessly, so the horcrux would be safe.