Modern Vespa

I have experienced on occasion that when I turn the scoot off and flip the kill off my scoot will not start. Usually a hard resent of the system solves this problem. Looking around on the forums it might be a spark plug cap issue. My question is How do a check the plug for this issue? Step by step would be helpful because unlike oil and all those other DIYers I'm a little apprehensive about messing blindly with a critical component on my bike (especially one that can be damaged easily).

The spark plug issue most people experience is the cap coming loose from the wire: the wire is very short. Pull the cap off the plug, inspect the cap is tight on the wire, it's a screw on cap BTW.

Your issue does not sound like spark plug related. Maybe a faulty kill switch.

What you have described is definitely NOT a spark plug problem.
It sounds like you could possibly have a kill switch that is going bad (or other things). Buy a can of electronic contact cleaner and spray it inside the kill switch by putting the little tube that comes with the contact cleaner against the edges of the kill switch. Then, toggle the kill switch about 10-15 times to make sure the cleaner gets on the contacts. IF.............that is your problem, it will probably cure it unless you have a contact that is loose and is about to break off (which is not likely).
Good luck.