[YZF]

It really depends on how much such travel happens in said corporation. I've worked for companies that handled this well and others where they were generally clueless. Most large companies will have immigration lawyers that work with them but usually the trivial business trip doesn't go through a lawyer.

How much and what types of questions you're asked can depend on many factors. Whether the officer had a fight with his wife, your profile, how his day has been going etc. Sometimes it's "have a nice day" and sometimes it's a longer interrogation including secondary inspections.

This is a common misconception that work means having a contract with a US employer. As another example you're not allowed to work remotely for a non-US employer while physically being in the US.