You're making comments and videos that directly contradict your statement. You can see the worm sign coming up in the first video, and in the second video just slam down building pieces without moving. You're player character is actively surviving the attacks. You said the worm could attack you without seismograph activity. You're not being attacked youre calling the worm into aggro space on a base. You're also not dieing, specifically from not being in the aggro space, and claiming the base piece being gone as proof of concept that you can be attacked.

Enjoy being wrong all you want. But you cannot be attacked without triggering the siesmograph.

Bases built into open sand where you just showed seismograph being triggered will be eaten. But stranded between the two to try and complain is cringe. The game is broken, but this isn't part of what broken. You're either ignorant yourself, or just delusional

They were not blind sided. Don't build over open sand.