The law is responsible for being just and reasonable, and not fining people for things they have no control over. There's no sure way to verify that a user is over 18[1], and I do believe that there's responsibility on parents to be monitoring their children - That if a 13 year old is creating accounts on over-18 websites, it is partially the parent's failing for allowing them too much unmonitored access.

Quite frankly: I want 17 year olds to use Tinder, figure out how it works, and understand the problems therein. I want kids to be able to tip their toe in anonymously to adult activities. Any hard-line requirements create a nice hard line - People who have no experience with X, and people who are expected to be experts with X - And that's how you create a feeding ground for predators. 17 year olds don't have to be able to recognize that a 40-year old man who's hitting on them despite the fact the 17 year old lied about their age is not a quality catch - They have to have support networks and enough opportunity to test the waters to figure that out before they get caught in a predator's web. One of the most important tools towards that is the ability to create anonymous accounts and explore, with understanding but without consequences.

[1] I won't iterate over the ways that is true, and I won't iterate over the ways that your perfect age verification is either a) broken or b) totalitarian and broken.