Laurel Reward missing!
This was a bug with the month of March, and ANet has since fixed it. Your friends abused the bug before it was fixed is how they got extra laurels.
[VZ] Valor Zeal – Stormbluff Isle – Looking for steady, casual-friendly NA raiders!
That is how it is supposed to work.
From the patch notes.
Daily and monthly laurels can be obtained through either PvP or PvE achievements. You cannot earn additional laurels from doing both, players can simply chose to do one or the other. They will still receive all other normal daily/monthly rewards should they chose to do both PvE and PvP achievements.