It's still possible to circumvent this by creating a one-liner using semicolons. Just grab a code like [2] and append `; rm -rf` to the selection. If the original selection was a one-liner, it'll still be.
I've tried various ways of input to my console (MINGW/WinXP) for multiline pastes, and the results are as follows: 1. Right-click multiline paste: unsafe (executes immediately) 2. Windows paste (alt-space, e, p): unsafe (executes immediately) 3. Insert or Shift-Insert: safe (pastes only the first line)