Lanefan
Victoria Rules
In a game where xp are given individually for what a character does (as opposed to what ideas it comes up with that others then carry out), yes - this can be an issue.That's my point. Those players should get over themselves. Those players not only got to completely come up with the idea, they convinced the other players that it was a good idea, and then they saw the idea they came up with entirely work out to a T... And yet that's not enough for them? They also need their "PC" to be the one to do it 'in-game', otherwise it doesn't count?
IME (and I include myself-as-DM here) when looking over things later in order to assign xp the DM will remember (or have noted down) who actually did what but won't nearly as often note or remember who came up with the idea for what. Part of that is because there's no risk attached to thinking but there can often be risk attached to acting on those thoughts, and risk is what earns xp.
As an example Corinda - a clanky heavy Fighter - might be the one who realizes scouting around the back of the castle could be a good idea but if it's Jarrod - the party's Thief - that actually does the scouting (and thus takes any associated risks) then Jarrod gets the xp.