I'm glad to hear that you'd agree with me then that a correction saying "there is no glass" would be inappropriate because when someone says glass they mean the clear part of the tank.
This may or may not be your intention, but fyi you are coming off as extremely condescending bordering on /r/iamverysmart level tones.
I'm no expert, but I know that a hot tub on slightly uneven ground has a good possibility of bursting and ruining the tub due to how much stress the water will unevenly put against a side. I don't see why the same underlying reasons wouldn't apply here too.
