The pain when you understand great music sometimes goes out of the scale to great effect and that staying in the same key won't guarantee what you play doesn't sound like crap.
The problem isn't if the notes are in the same scale necessarily, the problem is rather if you are actually saying something with your sounds that anyone else cares about?
When I'm on the dance floor I don't give a rats ass about if a track stays in the scale. The only thing I care about is if what is played is great and makes want to (continue to) dance.
That's not to say you shouldn't learn about keys and scales, but do yourself a service and don't assume limiting yourself to one key or scale is a short cut to how to write a great track.
If your ideas are always staying in one key, great. but chances are you're stifling yourself and your natural musical talents with assuming things must be in a certain way. It's the same thing when you assume the grid must be the norm for time. The grid could be killing your natural flow. Decide yourself how you want your music to flow. Create your own dogma.
Remove your shackles and be the great musical human you already are! Don't assume! Don't accept limitations unless you choose these yourself, not out of fear of sounding "wrong", but for artistic reasons.
If all you want is to make Country EDM, then just forget what I just said.
Thank for your reply. I was already aware of all you said but sadly my question still remains unanswered. Also, I strongly disagree with you about the knowledge of keys. Of course you can, and probably should, use non-diatonic notes for a song. However, knowing the theory is the difference between an engineer and a 'tinkerer'. The tinkerer may occasionally comes up with gold and the engineer may not, but at least the engineer will know why.
Thanks anyway though for taking the trouble to reply.