In practice, the negative double is sometimes used as a sort of catch-all, made when no other call properly describes responder's hand.
This is largely due to the special value that tournament play, especially the pairs game, places on major suits.
However, most negative doublers play that a new suit response (or free bid), whether at the one level or higher, is forcing.
The negative double loses even more definition when it can be made with a very broad range of strength, from roughly six HCP up to game forcing values.
The negative double does not cause the partnership to completely lose the ability to penalize an overcall.
These situations are rare, though, and the more so because some five-card major partnerships play negative doubles over minor suit openings only.