I suppose it depends on what you consider safe, what your treatment involves, and how much patience your orthodontist has.
If you have to wear elastics, you could wear the the minimum amount of time your ortho recommends (or less). Doing that month after month, though, your ortho might get frustrated with your apparent non-compliance. As a result, they might take steps with your treatment that don't require as much compliance, or maybe even drop you as a patient if you come across as too stubborn or recalcitrant.
Something else that you could do is, as you get close to the end of treatment, bring up little things that you still want corrected or changed. If you orthodontist wants you to be happy with your result, they may spend more time to work on those concerns. That can only last for so long, though, and they would have to be legitimate concerns.