Not a risk because of every company of VPN if it free or paid is first priority is to secure the privacy and protection to our customer. The Just difference between free and paid VPN is major differ is a Free VPN has maximum 5 servers allow and the Paid VPN is too many servers that are paid VPN is Highly protected then Free VPN.
I would say that the experts are right and certainly "in the end, you get what you pay for."! Recently a report by CSIRO revealed that most of the VPN providers are using malware to track users' data down in this report (https/research.csiro.au/ng/wp-content/uploads/sites/106/2016/08/paper-1.pdf) and if you notice the brands, then you'll definitely find that most of these are free services!
Another string case about free VPNs came out last year where Hola was accused of using its users as exit nodes. So it is absolutely true that using a free VPN service is never a reliable or safe option. They can be a huge threat to your privacy and even your security. You can never be too sure about whether they are legit or merely honeypots (https/www.purevpn.com/blog/free-vpnsproxies-as-honeypots/) so, I think the experts are right about the fact that Free VPN apps do not worth the risk at all!