ah yes

code/__HELPERS/roundend.dm

@@ -642,4 +642,4 @@
 /proc/get_fake_ckey()
 	var/first = pick(GLOB.first_names)
 	var/second = pick(GLOB.last_names)
-	return lowertext(first + second + rand(1,99))
+	return lowertext(first + second + num2text(rand(1,99)))

code/modules/client/preferences.dm

@@ -247,7 +247,7 @@ GLOBAL_LIST_EMPTY(preferences_datums)
 	/// Which of the 5 persistent scar slots we randomly roll to load for this round, if enabled. Actually rolled in [/datum/preferences/proc/load_character(slot)]
 	var/scars_index = 1
 
-	var/hide_ckey //pref for hiding if your ckey shows round-end or not
+	var/hide_ckey = FALSE //pref for hiding if your ckey shows round-end or not
 
 /datum/preferences/New(client/C)
 	parent = C
@@ -373,7 +373,7 @@ GLOBAL_LIST_EMPTY(preferences_datums)
 					dat += "[medical_records]"
 			else
 				dat += "[TextPreview(medical_records)]...<BR>"
-			dat += "<br><a href='?_src_=prefs;preference=ckey_hide;task=input'><b>Hide ckey: [hide_ckey ? "Enabled" : "Disabled"]</b></a><br>"
+			dat += "<br><a href='?_src_=prefs;preference=hide_ckey;task=input'><b>Hide ckey: [hide_ckey ? "Enabled" : "Disabled"]</b></a><br>"
 			dat += "</tr></table>"
 
 		//Character Appearance