Actually TIEA's and DTA's are not dangerous, they are just something developed by the OECD. Operating a legal offshore company or low tax company will not course any harm also not with the widely fear spread by other Offshore company agency's about this topic. If some are up for money loundering or other criminal activity this person will have to fear the DTA, TIEA and involvement of authorities, otherwise not 🙂
Spain has definitely signed with Netherlands Antilles, Aruba, Trinidad and Tobago, Bahamas, Cayman Islands, Andorra, and they're in negotiation with Gibraltar. That was what I found on Google. There could be more.
Yes, that's why Seychelles is particularly desirable at the moment. And why it's convenient if you happen to live in a country that hasn't signed many 🙂
DTA = Double Tax Treaty and it is a benefit if you can proof that your business is managed and operated in the country where the lowest corporate tax apply!