Type the command "/res tpsign", then bury a sign in the ground, and place a pressure plate on top of the block right above the sign.
I knew something changed, but wasn't too sure anymore. Ha, that explains why I kept teleporting to my storage while walking across a specific block on my farm Very cool feature though, when properly used of course
That's most likely happening by accident. Thing is; this behavior changed not too long ago; before that you needed to trigger the teleport sign (for example by using a pressure plate). And since you can also use teleport signs "manually" (by right clicking)... So its very likely that people may have placed a sign somewhere with the intention to use it 'manually' at a time when walking above it didn't trigger also trigger it. Well, either that or you may also be the first person to actually have stepped on that particular block Or, also a possibility, someone is playing games on you 8)
Pretty sure pressure plate was always optional. Not so much in this way, but since I joined the Empire 3 years ago, you could use nether portals for teleportation in this way.