Nothing of the kind. There are many sites which use their visitors to mining cryptocurrency and some people are wondering why their computers overheating ..
CryptoStop blocks resources, domains and IP addresses, that are known for spreading cryptocurrency mining javascript code using the visitor’s browser and hardware. It uses a blacklist of IP addresses, domains and a special javascript patterns to detect such intrusions and prevents them from loading and executing.
RE: Bulgarians created a free extension for blocking scripts which mining cryptocurrency