Curious About Funeral Wishes From The Deceased.

I'm 26 so I'm not too worried about this at the moment, but I do ride a motorcycle and enjoy riskier activities like skydiving, ziplines, bungee jumping, etc.

During a conversation with my mother a while back, she asked me what I would want if I ended up a vegetable from a motorcycle accident or something similar. During this discussion I told her I wouldn't want to be kept alive, and if I was showing no brain activity or signs of improvement to "pull the plug and bury me."

My issue is that my mother (60), very casually, said "no, if you die before me your father and I are cremating you and tossing you in the ocean, not putting you in the ground."

I really don't want to be cremated. I want to be put in the ground, not in some fancy ass coffin, a bare pine box would do, but I want to be returned to the earth. Hell if I had the money, I'd prepay for a reserved spot at one of those facilities that essentially composts bodies to be returned to the earth as fertilizer or something.

Worst case scenario, if I die before my parents, short of paying and arranging everything for myself in advance, would there be any repercussions for them if I signed a will stating that I want to be buried and they had me cremated and spread anyway?

I love my parents but they clearly don't care at all what I want to happen after I die.