I have meant to delete a line item multiple times and I have accidentally deleted the whole order. I think if the line item button was changed to say "Remove" it would be a lot less confusing.
We've had that same issue where a user wanted to delete a line but instead mistakenly deleted their order. They see the delete label and click. Your renaming suggestion reduces user confusion.
Originally wanted to move the delete button into the actions drop-down menu. Make it a more deliberate two-step action. Unable to figure how to move it though.
Ended up adding a password to the delete button. Using DELETE in all-caps (follows the MailChimp delete method). User feedback says this has saved them plenty of times.
Settings >> Sales Document Settings >> Sales Document Delete Password
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