Do you think 'explicit consent' is required before sex?

I teach criminal law, and we cover rape law. I always show them the Antioch guidelines, which were the guidelines that university developed years ago for consensual sexual activity and required consent at every stage of activity. The sexual assault policy is actually longer than this, but the part pertinent to consent reads like this:

CONSENT
Consent is defined as the act of willingly and verbally agreeing to engage in specific sexual conduct. The following are clarifying points:
• Consent must be obtained each and every time there is sexual activity.
• All parties must have a clear and accurate understanding of the sexual activity.
• The person who initiates sexual conduct is responsible for verbally asking for the “consent’’ of the individual(s) involved.
• The person with whom sexual conduct is initiated must verbally express “consent” or lack of “consent’’
• Each new level of sexual activity requires consent.
• Use of agreed upon forms of communication such as gestures or safe words is acceptable but must be discussed and verbally agreed to by all parties before sexual activity occurs.
• Consent is required regardless of the parties’ relationship, prior sexual history, or current activity (e.g. grinding on the dancefloor is not consent for further sexual activity).
• In order for “consent” to be valid, all parties must have unimpaired judgment and a shared understanding of the nature of the act to which they are consenting, including the use of safer sex practices.
• A person cannot give consent while sleeping.
• Silence conveys a lack of consent.
• At any and all times when time consent is withdrawn or not explicitly agreed to, the sexual activity must stop immediately.
• All parties must disclose personal risk factors and known STIs.

I present it to help anchor a conversation about what consent is in criminal law, whose burden it is to show consent, etc. One thing I think is interesting is that, as the years go by (I have been teaching this class for eleven or twelve years now), the students think that asking for and receiving explicit verbal consent is less of a weird or unrealistic idea. They seem to be more comfortable talking to their partners about what they do and do not want, and seem to think it is less of a mood-killer to make sure everyone is on board for sex. I am not sure what underlies that shift, but I do think it is worth noting (although I have no idea if that is just a shift that I am seeing or if it is actually representative of the changing attitudes of young people).