And maybe they are two children that are younger that 10 and in Japanese mindset nudy taboo is not applicable to them. For all flack Japan get about being perverted I kinda notice that western audience is even more so and manages to find fanservice where Japanese one do not...
Nanoha is a spinoff from an eroge, aimed primarily at an adult male audience, and its transformation sequences are rather sexualized (seriously, compare Nanoha's to Precure's - what Precure, aimed at preteen girls and thus not sexualized at all, notably lacks is step-by-step stripping of its characters, complete with camera angles to emphasize it). From there it's pretty reasonable to assume that fanservice was their intent when it might otherwise be a bit ambiguous.
Also, I just opened up the hot springs episode to verify that I wasn't just misremembering... and Yuuno's reaction to a blithely unaware Nanoha naked in front of him is a
rather strong indicator that the nudity was not intended to be just no big deal. With regards to audience-directed fanservice: the still shots of the girls are pretty much stock hot springs fanservice shots, they spontaneously develop curves and inexplicable back arches for half the shots when they're in towels, etc. It's not a huge offender, especially by today's standards, because it's not constant and it's fairly constrained, but it
is there.
Of course, the fanservice is hardly that episode's greatest sin; much like the rest of the first half/two-thirds of season one, the pacing is just so
bad. And ye gods, the art. Much off-model, much paper doll - and its art was hardly impressive to begin with. I remain in support of introducing people via the first movie, rather than the first season.