Spoilered for info on Tenchi Muyomidorininger wrote:actually for a clip show it works nicely. they arent just chilling reflecting on the past battles/year, they are coming clean on a secret theyve been keeping from someone who cares for them. and ... that theyve been mooching off of. which in japanese TV never seems to be a big deal with strangers suddenly move in and its ok. (tenchi muyo being the worst case of this)
Spoiler
(In Tenchi Universe) the grandfather knew who Washu was in advance and would have sensed that Sasami and Ayeka were distant relatives of his. Mihoshi and Ryoko had the "nice body" thing so one can understand why he wouldn't kick them out of his three guy zero girl home.