Although there are many children online, there are just as many teens and 20-somethings you try to break the rules in order to mess with people and younger or inexperienced players.
It's not safe for anyone under 12, and it's not a game that has any positive potential for 12 and up, either.
Disguising of language to try to bypass filters is looked for by moderators, and is most always found and punished. Parents should know that users can also create their own ads to solicit items that they have created which feature images and captions (which are both moderated).
Also, ROBLOX has recently been showing video ads for different companies before users enter a place (these companies are generally ones such as insurance, phone carriers, car companies, and etc. Although Roblox does have its flaws, it is mostly a friendly game that encourages children to build and program.
Parents be warned - the moderation on this site is less than fair.
My son reported an abuse and he was reprimanded as if he were at fault. The language used by the gamers is less than desirable and poorly moderated, the focus of the games are generally violent which is inappropriate for the younger crowd.
but the account is still there to 'go back to'.
The site does NOT support online dating, and will take moderation actions on kids that pretend to have "girlfriends" or "boyfriends." Language is not an issue at all.
In game chat filters, as well as over the website, there are filters that filter any language besides the minor "hell" that players might try to shout out. There are MANY ads that link to different companies which are place in banners and rectangles all over the site.
Although this does not often happened, and is exaggerated by parents, the fact may be their fault because they are leaving their kids uneducated; this is probably the main reason that privacy is an issue.
Another complaint that many parents had was the online dating factor.
Privacy is only an issue if kids are not taught to be safe.