If you are in a Roomette, especially with another person and elect to carry on anything above a small Pizza, you will likely have to take it to the Lounge as now adding a Pizza Box to the mix of what you are putting in the Roomette may be too much. But if you take it to the Lounge, other pax may lay Siege on your table wanting to remove the Pizza from your possession!
That is when I wish I could carry my Halberd with me to fend the Attackers off
I think that you should be fine with that - or maybe an epee'.
I just looked at the rules, and:
Sharp objects, including but not limited to axes, ice picks, knives, spears, and swords
*Scissors, nail clippers, corkscrews, and razors are allowed in carry-on baggage.
**Sheathed equipment, to include fencing equipment, are allowed in checked baggage.
A halberd is not
specifically listed as a prohibited weapon. The again, neither is my mace (as in the spiked-ball on a chain type) nor my set of bolos.