Regarding @
The_woo and the various issues raised in that post .... seems to me you patronize a crappy shop.
If I were a bike salesperson (and I have done my share of sales, so this isn't my usual pointless crap--this is Informed pointless crap---) One rule of selling is "Up-sell." Another is, "Create return business."
"Excellent choice, sir or madam. I certainly enjoy having tubeless tires on some of my bikes .... are you up to speed with the technology, and do you have the appropriate sealant, tools, and patch kit?" (No way I would ever let a bike out the door without pushing for a seat bag, mini-pump, two spare tubes, patch kit, and boots. Not anything unethical either, because I wouldn't go out my own door without those things (and obviously, tubeless-focused gear if the person was riding tubeless.)
"It is recommended that you don't mix sealant types in the tire. You are set up with X-Brand right now. I'd suggest buying this x-ounce refill bottle, because you will need to top of the sealant a few times a year. This bottle will easily last a year. And using this valve-core wrench is a lot better than trying to improvise and damaging the valve. We also have this mini-syringe and tube which fits perfectly over the valve. I use this system and if I am careful, I can add sealant without spilling more than about two drops.
"Also, while you can put a tube in a tubeless tire, a lot of times you can just patch the tire with this Brand-XY cured ham product. The kit comes with clear instructions, but I can also explain really quickly. You probably won't get three flats in a year, probably not even one, unless you ride a hundred miles a week, that need any attention at all, or maybe just a squirt of air after the sealant does its job, but for that one time .... "
That gets me more sales, and a repeat customer who realizes that I know at least a little stuff and actually want to help him/her enjoy the ride.
If you are giving money to a shop which isn't giving good service, that's on you.