Mik,
1. Who says that it is a good minhag in our day? It originated because Jews were afraid to go outside on that night as Xtians got drunk after hearing fiery anti-Semitic sermons and they were too poor to have sefarim in their homes.
2. Someone who is mitzta’er is halachically exempt from sleeping in the sukka. This is, of course, subjective. I heard that they are mitzta’er because they cannot feel the or makif (@Neville).
3. You yourself wrote that this is only the ideal. However, it is legitimate not to do so. This is why someone who forgets “retzeh” in birkat hamazon does not have to go back.