It sounds to me that you are just curious about a policy you saw on a website, and I am answering on that basis. However, the below can not be taken as legal advice. If you are looking for actual advice, you need to discuss the matter with an attorney licensed in your jurisdiction who is conversant with all the facts. The below is just a sketch of some points about subpoenas, and I have nowhere near enough facts to advise you on how a subpoena might affect you in reality. Nor am I licensed in your jurisdiction. You are not my client. I am not your lawyer.
The touchstone of the subpoena is that “the public is entitled to every man’s evidence,” even if he has no interest in a case. (And even if devliering his testimony burdens him to some extent.) However, there are many exceptions.
Subpoenas aren’t that much of a headache – you can draft a good one in an hour or two, especially if you know with specificity the information you want to elicit.
Who can issue a subpoena depends on jurisdiction. In civil cases in the federal court system, any attorney licensed in either the federal district where the subpoena is served or the federal district where the case is pending can issue a subpoena. In some other jurisdictions, a party must apply to the court where the case is pending, and the court can then issue the subpoena.
The time to reply to a subpoena is typically filled out by whoever issues it, within limits prescribed in the jurisdiction’s civil rules. In the federal system a subpoena must give “reasonable time” to respond, although what amount of time is reasonable is a case-by-case decision that is ultimately up to the court if the issuer and the target cannot agree. (I would guess that “reasonable time” coule be really short for a case like this, where the issuer would want one file on one easily-identifiable person.) At a minimum, the target has 14 days to object to the subpoena. Other jurisdictions have other timing schemes.
Of course, just because a target receives a subpoena, it doesn’t necessarily mean that the information requested will be given over. A subpoena does compel production of the requested information as a baseline, but there are limits to its power. A target can object that a subpoena is overbroad or burdensome, that it was served improperly, that the requested information is privileged, etc., etc. “I don’t wanna tell” isn’t a sufficient objection, nor is “I promised I wouldn’t tell,” but there are objecions that can defeat a subpoena, either in general or w/r/t specific requests or specific pieces of information.
Usually, after a subpoena has been issued, the issuer and the target negotiate on exactly what is to be produced and when. Both sides have some firepower here; the issuer has the power of the court to enforce all his requests if they can’t agree. OTOH, but the target can move to quash objectionable requests. Even if he loses, it’s going to tie up the issuer’s resources and delay the receipt of the actual material. So to avoid litigation on the scope of the subpoena, both parties are typically willing to reach accomodation.
Other types of subpoenas exist. Grand juries can issue them as can Congress in certain circumstances (I don’t know the mechanics there). They are in essence the same as a civil subpoena and absent special circumstances, a target would have to comply with them the same as a civil subpoena.