value of ref=* displays on nodes

[skorasaurus]

I found one test case, http://www.openstreetmap.org/node/2323174682 where the value of ref displays at zoom levels earlier than 18.

I did another quick test, ref=* also displays for amentiy=hospital, amenity=parking, leisure=park, not for leisure=playground

I need to:
write a general rule to not display ref values in nodes below a zoom level of 18 and to style the text as well (with a halo, to match our other text-display rules)

• can find out what iD does (to determine what rules/situations to display ref=* and then tweak it for any use cases in our contexts.