Name a population (other than those mentioned in the topic) for which snowball sampling might be better than other types of sampling. Explain the reason(s) for your answer.
My first instinct is to say that you are going to be looking for people who do not particularly care to have the information which you are attempting to study known about them. This is the factor that determines the need to use snowball sampling. There will not be an easy, convenient, or well-populated location to collect these participants from. With that premise, you will likely be looking for something that is either illegal, socially unacceptable, or perceived by the participant as being shameful or exposing a weakness. These types of participants will all have reasons that they would not want the information being publically known. As examples, prostitutes may fear prosecution from the law; those with sexual interests which others would find objectionable might fear what others would think of them; those suffering from any of a variety of mental disabilities may fear that the disability would be taken as a sign of weakness or a defect by others, or that someone knowing their issue may manipulate them or take advantage in some other manner. To effectively use snowball sampling you will need to be able to establish trust and be able to ensure anonymity.
In each of these hypothetical groups, there are those who might be willing to talk with you, perhaps more than a few, but those people would fall into a different pool for sampling as willing participants. For snowball sampling to be the best method, you have to be seeking those most motivated not to have discussions with you.
I am not completely sure you have a complete grasp of the snowball sampling method because no where in your post did you mention the need to come into contact with at least one subject individual relative to your research. The snowballing method hinges upon that one individual bringing you into contact with subsequent individuals that may be otherwise unreachable. Your examples of individuals and research subjects certainly do qualify for the possibility, and maybe even the necessity, for snowball sampling. If your response works on the premise that the reader knows that you know the conditions that lead to snowball sampling, then I respectfully retract my comments and simply say that these are excellent examples of other potential sample subject that my be very difficult to get in touch with through any other means than snowballing for the reasons you mentioned.
I thought that with the question being to name a population for which snowball sampling might be better than other techniques established that was the topic of my writing. You are right in that if someone did not realize the implication then my post would be confusing. I did take it for granted that the reader would understand the subject. Even though we all should be aware of what it is, as a technical point you are entirely correct that I should have established some basic parameters of what I was discussing. While it should not be necessary in this context, it would be a good habit to maintain so that I don’t make those assumptions when they aren’t applicable. Thanks!