Exactly. Being nervous, of a "suspicious" ethnicity, giving any indication that you're being paid for being in the country, can probably all lead to issues. As

Exactly. Being nervous, of a "suspicious" ethnicity, giving any indication that you're being paid for being in the country, can probably all lead to issues. As I wrote elsewhere, aside from some countries that require a visa for any explicit business activity, a basic visa is typically fine to go to a conference or meet with a customer, much less send some emails.