Warning text about changing sponsorship benefits

diff --git a/docs/confreg/sponsors.md b/docs/confreg/sponsors.md
index 8862e667f6b2f189d1b65dee0b28332e40c4e848..d78d19ed179b3a9c9b793f1a2f1d7bab08b511dd 100644 (file)
--- a/docs/confreg/sponsors.md
+++ b/docs/confreg/sponsors.md
@@ -41,6 +41,11 @@ To set up sponsorship for a conference, in order:
 1. Create one or more [sponsorship levels](#level).
 1. Open sponsorship on [the conference](configuring).
 
+Note that the *benefits* should **never** be changed after sponsors
+have started to sign up, but there is nothing in the system actually
+preventing it (things like fixing spelling and wording is of course
+always allowed...)
+
 ## Sign-up process
 
 The sign-up process looks slightly different depending on if the