It's entirely possible that they might not be aware. Surveyors are concerned with measuring bearing and distance from an arbitrary location (5000,5000) in some cases. The distances they traverse are not enough to see differences between US Survey foot and Int'l Feet. Cartographers and GIS folks who tie into a photogrammetric basemap are probably more aware. Most Civil engineers are like 'NAD83? Ok, whatever you say~!'
This is true. I barely understand coordinate systems enough to get by and somehow I know them better than any other engineer I've talked to. Surveyors are 50/50 on whether they know all that stuff or not.
Really though, there's no excuse for errors caused by that stuff. Survey data should almost always only be used relative to itself.