Depends on your definition of "safe" and what exactly you are referring to.
If you mean getting a cape through TeamView/GoToMyPC/etc. then yes, that is considered safe.
But "safe" is not a 100% guarantee that you're golden, who knows maybe they find a way to bust these capes in the future, and as a result retroactively removes all capes obtained this way. I don't personally see how that would ever happen though, but who knows. But so far it does seem to be gg as nobody has really reported getting banned for a Teamview'ed cape, without also having also done other stupid stuff or having a history of getting Infernal capes via less "safe" methods and then getting future Teamview capes removed as a result. If you got caught in the past, your account is flagged and your future capes are likely going to be removed too. They removed all these "repeat" capes in the latest wave, even if you got the latest cape 100% legit.