For most people, probably not. Just in case you do not know what unlocking is; unlocking your cell phone allows you to use a phone carrior other then what is ‘locked’ to your phone. For example, if you bought an iphone that is locked to AT&T, you can ONLY use AT&T. However, if you ‘unlock’ your phone, then you can use t-mobile or another carrier that perhaps will give you a cheaper / better plan.
If this is really important to you, you may want to run out and buy a phone right now because starting tmmw, its illegal. Now does that mean the phone police are going to come knocking on your door tomorrow? Not likely, but that will give them yet one more way to ‘not’ support your phone if something goes wrong. Also if you unlock phones as a business or worse, steal phones, them might find things getting a little more hot down the line.
The good thing is you can buy unlocked phones if you really need to be able to switch carriers and hate dealing with unlocking your phone. Also, there is not currently a software unlock for the latest iphone, so its not like its going to matter in the short term. That being said, there are services out there can unlock the phone for you be getting the unlock code, however I have never tried it on the current iphone 5.