you can buy connector safety clamps to prevent such things, or some simple sticky tape will do the job, or double back the cable and put an elastic band around (less messy). If you need a return spring because of the fear of the battery cable failing make sure the battery connections do not fail and the failsafe will do its job.

For most little problems use your imagination and look around your house for helpful items (pen springs, spray bottle tubes for emergency antenna etc).

You don't need to buy every little thing from the manufacturer IMAGINATION goes a long way.