False Assumption #1: Maryland law prohibits the "taping" or "recording" of conversations without the consent of all persons.
The Truth #1: Maryland law prohibits the "interception" of "communications" without the consent of all persons to the communication and does not even mention "taping" or "recording" anywhere in the part of the statute related to criminal violations.
Explanation #1: Maryland law states the following verbatim:
Unlawful acts. -- Except as otherwise provided in this subtitle it is unlawful for any person to: (1) Willfully intercept, endeavor to intercept, or procure any other person to intercept or endeavor to intercept, any wire, oral, or electronic communication;
(2) Willfully disclose, or endeavor to disclose, to any other person the contents of any wire, oral, or electronic communication, knowing or having reason to know that the information was obtained through the interception of a wire, oral, or electronic communication in violation of this subtitle; or
(3) Willfully use, or endeavor to use, the contents of any wire, oral, or electronic communication, knowing or having reason to know that the information was obtained through the interception of a wire, oral, or electronic communication in violation of this subtitle. Cts. & Jud. Proc. §10-402(a)(1)-(a)(3). (emphasis added)
Nowhere in the law are the words "tape" or "record" ever used.