Dockless Roombas
Dockless Roombas
[Cueball and Megan walk in from the right and sees two Roombas on the ground in front of them.] Cueball: Are those... Roombas? Megan: Yeah, the dockless rental apps have really taken off.
[Cueball stops and turns to look at Megan, who has also stopped, as Beret Guy comes walking in from the left with his smartphone in his hand.] Cueball: What?
[As Cueball and Megan turn to look at Beret Guy, he stops between the two Roombas, looking down at the Roomba to his left. He taps his smartphone and the Roomba makes a sound.] Smartphone: Tap tap Roomba: Unlock
[Beret Guy is squatting down on the Roomba as it drives him away, while Cueball and Megan turns to stare after him,] Roomba: Whirrrr

In this comic Cueball discovers two Roombas outside, and Megan explains that they are dockless Roombas for rent. Cueball is confused, but then Beret Guy walks in, activates one with an app on his smartphone , and rides away standing on it.
A Roomba is a small automated (robotic) vacuum cleaner designed to clean a room or other bounded area by repeatedly and automatically going over the floor, vacuuming, until it has made multiple passes, and either runs low on power or is turned off.  The "intelligence" of various models can vary from relatively random operation with basic techniques to get around obstacles, to models that generate a general mental map of the area and contents and attempt to be deliberate in passing over all reachable areas.  A Roomba generally includes a recharging "dock", which it can find and automatically connect with when it gets low on power, allowing it to recharge and perhaps automatically begin another round of cleaning. Roombas are a recurring theme on xkcd. In 1193: Externalities it was Ponytail that drove a Roomba. And in 1486: Vacuum Beret Guy flew on a regular vacuum cleaner.
A dockless scooter is a system of sharing personal scooters whereby they can be left anywhere for someone else to use, rather than returned to a particular home location. They are typically activated via a smartphone app. The term "dockless" in the name refers to the fact they have no predefined home, or place to dock. Like a Roomba, they do need recharging, but no special station is needed for that -- anyone can pick them up and recharge them overnight from a standard power outlet, receiving a fee from the scooter company for this service. In the past several years they have become popular in many large cities around the world. Scooters have recently been featured in 2188: E Scooters .
The humor here is replacing the scooters with Roombas, which people would then ride.  There are multiple problems with this idea:
The title text refers to the controversy in many cities surrounding dockless scooters, which can be dangerous to pedestrians when in use and can block sidewalks and driveways when not.  Dockless scooters were introduced in many cities before there were any regulations about scooter use, with some critics claiming scooters exploited loopholes in existing law and regulation, and leading some cities to pass legislation to specifically ban or curtail the use of dockless scooters. Here it is the Roombas that exploit loopholes in those scooter laws, which initially bothers city officials before they realize the positive benefit of the Roombas cleaning their streets as they are ridden.
[Cueball and Megan walk in from the right and sees two Roombas on the ground in front of them.] Cueball: Are those... Roombas? Megan: Yeah, the dockless rental apps have really taken off.
[Cueball stops and turns to look at Megan, who has also stopped, as Beret Guy comes walking in from the left with his smartphone in his hand.] Cueball: What?
[As Cueball and Megan turn to look at Beret Guy, he stops between the two Roombas, looking down at the Roomba to his left. He taps his smartphone and the Roomba makes a sound.] Smartphone: Tap tap Roomba: Unlock
[Beret Guy is squatting down on the Roomba as it drives him away, while Cueball and Megan turns to stare after him,] Roomba: Whirrrr
