Most states are either one party or two party consent states. One party = you can unilaterally record anything (not sure this includes things you're not actively involved with, e.g. spying). Two party = you must have consent of everyone in the recording.
By a plain reading of two party consent statutes, people are in violation if their home speaker records a guest without obtaining consent.
I'm sure Google and Amazon's lawyers would try to weasel out of compliance via claimed anonymization, but that's definitely not the spirit of the law.
Old, but thorough: http://www.mwl-law.com/wp-content/uploads/2013/03/LAWS-ON-RE...
You're also going to bump up into specific wording on whether a given statute covers only telephone conversations or oral conversations, as most of these are phone wiretap laws that may or may not have been worked ambiguously.
Additionally, there are federal statutes that likely also bear.