Quoted from Wikipedia about B holders automatically able to drive also A1 without any additional training:
"B licence holders in Czech Republic (only motorcycles with automatic and semi-automatic transmission), Italy, Latvia, Slovakia (after two years and only motorcycles with automatic transmission), Spain (after three years), Poland (after three years), Portugal (at least 25 years old or additional licence for mopeds), and Belgium (after two years) are allowed to drive motorcycles not exceeding 125 cubic centimetres (7.6 cu in) within the respective countries."
So roguhly 1/3 of EU population is fine just with B license. In other countries you just need few hours of training.
"B licence holders in Czech Republic (only motorcycles with automatic and semi-automatic transmission), Italy, Latvia, Slovakia (after two years and only motorcycles with automatic transmission), Spain (after three years), Poland (after three years), Portugal (at least 25 years old or additional licence for mopeds), and Belgium (after two years) are allowed to drive motorcycles not exceeding 125 cubic centimetres (7.6 cu in) within the respective countries."
So roguhly 1/3 of EU population is fine just with B license. In other countries you just need few hours of training.