There are several reasons why bet365 accounts can be restricted, including matched betting, unreasonable betting behaviour, GamStop (self-exclusion), and exploitation of bonuses.
Note that each country has its own set of sign-up offers and bonuses. In some countries, Bet365 offers a unique version of the site, such as their Spanish and Italian versions. On the other hand, the bookmaker is banned in Belgium, France, Portugal, the Czech Republic, and Russia.