Just in case anyone is curious, this is the simple fix I came up for this.
I created a new custom profile field and set the conditions to yes or no, single selection radio.
Then I added this code.
Code:
<if condition="$bbuserinfo[fieldx] != No">
.......
<else />
........
</if>
This way if you set Yes as default, then the header will show up, if the user changes it to no then an alterenate header will show up.
I did this because some users prefer a different logo on the header because the original one may not be work safe.
I know this is very simple, but figured I'd post it just in case someone else is looking.