Don't generalize and don't conclude from your point-of-view to the whole world. There are enough places where you can talk to the police without even thinking about a lawyer (and never ever even require one, even in such situations). Not everyone's country is the USA (I assume).
Obligatory IANAL.
Many of these kinds of warrants are closer to the "minor traffic ticket" side than anything else. The trouble is that you may want a lawyer to tell you that.
So wouldn't the alternative where they get the footage from someone else be just as bad as you turning it over without checking, and therefore something you should prevent if consulting a lawyer first is to your advantage?
That's one of many reasons.
Even if we aren't talking about court orders, any interactions with the police beyond small talk should be guided by a lawyer for the same reason. Arrogance has no place when interacting with the law, the complexity of which is far beyond the understanding of common men.
The problem is the side of it where you abandon in advance your ability do to that by giving a third party custody of your data and then suffer whatever consequences a lawyer might have advised you to avoid when the third party hands your data over to the government.
It doesn't matter if you're going to abide or contest court orders or whatever the hell else. I'm not talking about that.
You. Need. A. Lawyer.
Mere mortals cannot and will not understand the complexity and intricacy of law.
You. Need. A. Lawyer.
Having a lawyer do the basics is really cheap. Having a lawyer fight the warrant or craft a minimally-revealing response is expensive. You don't have to break the bank if you end up getting served a warrant.
Given it's common sense to never talk to the police without a lawyer, you would want a lawyer for this situation so you know you're not unintentionally fucking yourself over.
Obligatory IANAL.