On the subject of false glideslopes....
Yes they do exist but you should be monitoring distance against height as a cross check (thats why the GS height is given at various distances on the plate). You should definitely know where your DA is in relation to distance from runway
For example "passing 1500ft 2 miles to run looking for 300ft at 0.5dme"
I see a fair number of pilots at renewal who can tell me the Decision Altitude but have no idea where it is as regards distance.