Lol Im pronoid with my corners, I always check them. If you really have a problem with knowing callout spots it's best just too look at this or keep it own on your second screen when playing a particular map (if you own two screens of course).https://steamcommunity.com/sharedfiles/filedetails/?id=157442340
I use nades when I know someone is dinked.
And yeah, that's what can happen with pre-mades.. Not all are good.. As you can see here