That depends on whether or not you tell anyone aloud. The practice, however, is not allowed. (Sorry. I couldn't resist the usage correction. My mother was an English teacher).Are we aloud to select themes for our characters?
I don't see themes as that powerful. The extra encounter power is not alot stronger than an at will and after 1st level they just give a larger pool of utilities to choose from. They're kind of like a watered down version of kits.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.