hello,
There is several point to be checked :
- Privacy : Depending on country where you deploy DLP, you may have different degree of privacy allowed to end users. So you may have different pre requisite before being allowed to start running DLP on their email.
- Incident management : If in your activity there is some specific regulations, there may be some constraints related to that and they could be different depending on countries where you want to deploy DLP. This could lead to some specific way to manage DLP incident and some request for some seggregation of duties in the tool by defining new/specifc roles.
- Policies : For some statement as above, you may need to put some specific policies in place on some population or not allowed to apply some policies on some other population.
- As you wrote in your question, you need to take care about transborder issues as you will transfer data, and there may be some personal data in messages.
All these constraints must be validated by your company legal and compliance teams because this could lead to some major issue for the company. So i am a little bias on theses points as i used to deploy some DLp in europe where transborder DLP could become a nightmare.
Regards.