RE: Vanilla as a cover scent...
You cant cover your scent period. How do you think one deer can smell another that has walked across a cow pasture or corn field.
The smell of corn, dirt, cow pies etc. is must stonger than the spot where a deer stepped hours earlier but the deer can still track another with easy. Each scent has it's own molecular make up that deer can pick out with ease. This is why drug dogs can pick out the scent of drugs even when it's mixed with other things or how they can smell a body in huge pile of rubble. Each scent has it's on finger print so to speak...
If anything the vanilla can be used as a curiosity scent but thats all.