That can be solved with the right company culture and a good manager. If someone was disturbing my work in that manner I would mention it to my boss, who would

That can be solved with the right company culture and a good manager. If someone was disturbing my work in that manner I would mention it to my boss, who would probably tell me to not spend time answering them next time and direct them to the proper support channel. If it happened repeatedly, then my boss would escalate it with the salesperson’s boss.