Earlier quoted context omitted.
Hack their webserver, replace the contents of https://install.meteor.com/ with malware, instantly pwn anyone who pipes that to their shell. Worse: the people who are most likely to curl|sh are DevOps folks with the keys to their company's kingdom.
What do you want them to do? The obvious solution is to change it from "curl|sh" to "curl|{something about whetehr PGP says this is properly signed by the private key belonging to public key blahblahblahblahbalhMETEOR.COMkey. If yes:}|sh" But the problem is anyone compromising the site can just change the line from "blahblahblahblahbalhMETEOR.COMkey" to "attackerchangedblahblahblahblahbalhMETEOR.COMkey" right on the…
I want them to not use a one-liner. Step-by-step:
1. Download the files
2. Download the public key
2a. verify the public key if you've never seen it before (publish in the blockchain, have lots of high profile technologists sign it, etc)
3. If the verification matches, then proceed.
Teaching developers to value "clever one-liner hack" over "secure, dependable solution" will lead to bad habits.