I am renovating the bathroom and everything I see online says to tile over the lip. This creates one obvious problem - to replace the bathtub one would have to remove the tile, and since style and trends change all the time, you won't find the same tile again.
It would seem logical to tile up to the bathtub, so it can be removed if needed. Why is everyone tiling over the lip? Still have to use silicone between the tile and bathtub surface. I am almost at the stage of tiling and trying to finalize the plan.
The reason I started to doubt the tile over the lip technique is because I know someone who did tiling up to the lip and had no water problems for 15 years, at which stage they remodeled and all walls were dry.