It is NOT a violation of the T&Cs
https://www.hilton.com/en/hilton-hon...ard-redemption
Ironically what would be a violation of the T&Cs is if you redeem your points for somebody else (where the name on the booking is actually changed, not just adding an additional guest) and then you yourself attempt to stay - since you are no longer named on the booking
that’s ok of course, but not what the OP is trying to do which is indeed a violation. You can call and book an award for anyone. If you book for yourself and you add someone else’s name (to get the benefits) and you do not show up - that’s fraud.
Yes, most of the time this is not a problem. However, if the hotel insists, you better show up. This has happened to us twice in the past 30 years and in both cases it was simply my wife checking in earlier. They insisted I stop by the front desk when I arrive and they followed up (as I didn’t make this this a priority). So YMMV, but you are putting your account and status at risk if you book with a 2nd person and you are a no-show …