Is it safe to add **leading** underscores on reserved keywords for **columns**?

For instance: `_key`

There too many reserved keywords and it is hard to avoid.

For instance currently I am using `code` to replace `key` to avoid collision.

But what happens if one day they decide to add `code` into the reserved keywords? Then I have to find new keyword again or adding **backticks** - which is a lot do to maintain!