The pure software world exists from Google's perspective, they provide zero support and then it's just a matter of individual choice if you want to use the service or not.
Google can go a long way into making this significantly safer than random pick-up: you can select female only drivers or riders, only riders from your area, they can implement a minimal account age that uniquely identifies the wazer simply via ride history - even if they use an anonymous login and fake credit card data, and so on.
It's a bit harder to protect against rogue riders since they need to be able to use the app immediately, but still, phone number and credit card verification is much better the letting a random stranger into your car. If not too intrusive, they could even ask riders for a frontal picture that the driver can verify and that remains on record. So for people who would carpool anyway, it's a much better option.