Serious creative security issue by placing spawners that summon command block (Either Minecart or falling sand)

IMPORTANT: I hope I made this private. If it is not private, please make it so. It is not meant for the public.

A way to get OP if you have creative.
I am assuming you know about CrushedPixel's video, and how he can use his creative inventory to place down signs with NBT data allowing for getting OP when not. This was fixed. What was not fixed is placing spawners that summon command block minecarts with data in them, and then being able to power them.

ALSO: you can get a spawner that spawns a falling sand command block that allows for exploitation.

This was not tested thoroughly, but I feel like it is still an issue. I have asked Panda4994 to make a mod and test this. He is trustworthy not to disclose this information. I am going to guess that it works, as the fix for the sign does not fix spawners. I will not make any videos or release any of this to the public. I do not like drama.
No one else knows about this. I just figured it would work. But if I can figure something out, others can too. I am good at finding ways to break the game and finding bugs, but I will always be responsible with them.

You can message me on Twitter if you have any questions: https://twitter.com/TheNoerdy1221