Personally I would never be ok with the idea of blowing moisture directly at an electrical unit, no matter how many fail safes. With that aside however, what about airflow when the humidifier is off?. Lastly I would think that blowing humidified air directly up, it may get sucked directly into the out-take ''jet-stream'', meaning the moisture levels outside of that stream would be low, any plant foliage in that area could suffer low RH respiration issues.
The fact that your out-take can and is maintaining the heat of 1khps means there's very likely a strong jet stream.