If person 1 doesn't tell the group if they're adding their salary at the beginning or at the end, it would provide a little more security between person 1 and 2.
i.e. If the minimum rand # is known to be 100,000, and person 2 receives the number 150,000 and knows it includes the salary of person 1...they will know person 1 makes <= 50k
If the first person doesn’t add their number, then the 3rd person has the same “visibility” into the second person’s number, based on the minimum rand.
The solution can be to include negative numbers in the RNG range, or keep the RNG range a secret (except to person 1).
i.e. If the minimum rand # is known to be 100,000, and person 2 receives the number 150,000 and knows it includes the salary of person 1...they will know person 1 makes <= 50k