I've worn this White Covermale (cm 146) brief to a public hot tub. It is not vulgar at all before you get in dry but due to the very thin and unlined material provides alot of information when getting out. Sheer suits are always much less sheer during night time; I wouldn't wear this suit during daytime. (also beware of flash photography, slightly sheer suits can become near transparent)

Suits that are revealing due to lack of opacity rather than lack of coverage add a level of plausible deniability if you run into any complaints regarding the facilities rules on appropriate swimwear. I will say I have never heard a single complaint over many years of wearing much much more revealing suits than everyone else in a number of different locations. Your own fear regarding exposure is almost always a much bigger obstacle than anyone elses prudishness.