I will be staying at the Mandalay Bay Resort & Casino in April.  Can someone please opine on the ease or lack thereof of companions coming to the room? Do I need to meet them in the lobby etc.?

Unfortunately, they've changed it to where you need a valid room key to activate the elevators.

Pick out a spot to meet in the lobby or at one of the bars, preferably not too far from the elevators.  

At security by elevaters .😏

I usually suggest a near by bar or the gift shop.  And yes it is not just a flash of the key, you need a valid room key to activate the elevators.  So either pass on the extra key to your date or have her walk in with you to the elevator area. Have fun and enjoy

My policy is to meet in a nice lounge for a beverage, spend 30 minutes having a drink- which does not come out of our session time- and walk together to the room.  I also require the gent to walk me to valet after our session.  This raises no suspicion and, for me and my guys, adds to the experience.  
I see all these posts about elevator keys, etc., and it makes no sense to me.  Knocking on a stranger's hotel door is way outside of my comfort zone and seems...so impersonal.

We can meet and casually pass a key and no one will be the wiser!! If you are interested in seeing me while you are here just fill out my contact form on my website!