So they absolutely can arrest you for being in their presence; the minor caveat is that you have to be ordered to stop first, so you have some warning.
In practice, there won't be warnings. They'll say, out of the blue, "I told you to move away," and then arrest everyone in the vicinity.
Also, how does this bill treat cops approaching you? For example, even if the cops do give warning, what if they continuously walk towards the person warned? I think this law is ripe for abuse by cops, who famously love to abuse.
Well, that's super neat and very useful for my circumstances. I'm moving outside of the US soon to a place where WhatsApp is dominant, but I still want to use SMS/MMS with family and friends in the US since I doubt they'll make the switch. I've been using WhatsApp for about a year now while coordinating stuff for my soon-to-be home and I've come to the conclusion that WhatsApp is complete garbage.