Exactly. Bunches of them actually. If you've bought a gun through any FFL dealer they know you have guns. If you've bought any guns, ammo or accessories with a credit card they know you have guns. If you've joined any pro-gun organization they know you have guns. If you've ever sent a letter or e-mail to a Congress critter in defense of gun rights they know you have guns.
About 110 million Americans, 1 out of 3, own guns so there is really no need to be shy about it now.
Signing the WH petition is a far lesser proof that you own guns than they already have.