It's about as illegal as violating a TOS.
The EFF's interpretation of the TPP makes it also seem like for any member country, it could also be liable for criminal penalties.
IANAL
...which in the US, due to the joy that is the CFAA, is pretty illegal and could result in jail time.
https://ilt.eff.org/index.php/Computer_Fraud_and_Abuse_Act_%...
https://www.eff.org/cases/united-states-v-drew
It's about as illegal as violating a TOS.