The First Week After Disclosure?
(First 48 to 72 hours) Personally I think if the hypothetical scenario you described ever happened then, every country on this planet would deploy all their military resources. Eventually one of the more distrusting country's would get "trigger happy" and they would follow the shoot first ask questions later philosophy and then the S**t would hit the fan.
I think whoever these beings are they would probably be aware of this type of reaction from humans so I really doubt anyone with "good intentions" would show up over our planet in that many ships. And hypothetically if this scenario involving that many ships ever happened....RUN & HIDE!
On a serious note: Many, MANY people are assuming some sort of disclosure is on the horizon. "Disclosure" is just the latest buzz word/topic in ufology right now and lots of people are jumping on the band wagon. In my opinion the type of disclosure people are clamoring for right now will never happen. Also, (at least in the U.S.) more specifically, "government" disclosure is an impossibility because long ago the government was taken out of the loop as far as any information that might be known about ET or whatever they are. In the United States and many other countries if their is any information on the "ET" topic that can be disclosed then that information is held in the highest levels of the military and certain intelligence services. Sadly both groups will operate outside the law when it suits them and they always have the excuse of "national security" to fall back on when they need to justify any illegal actions.