The EU law (TKG Telekommunikationsgesetz) criminalises necessary communication methods that are common practice in daily business !
Strictly speaking you must not send a singel e-mail to somebody you just met at an event.
If you can not satisfactorily show what business case exists to this person, what you can do only using a sophisticated Sales Situation Management www.e-mem.info, this may have serious consequences.
Any businessman with half a brain is glad to get interesting offers,
declares himself within his own malings to get many contacts
and will respect deregistration and bans on mailings (free accessable Robinson lists).
Unfortunately this law will not protect as against "V G I * R A", "P * R O N O" and Co. !
Bureaucrat should do anything againgst this !
A slowdown in information interchange will lead to serious disadvantages for European companies over USA and Asia ...