Actually concrete dosnt seal everything, when bodys decompose they release gas that can create pressure then cracks. Also theres tools that let you see the volume of large peices of concrete without digging anything up.
Yet another guy getting blasted online for asking a girl out HAHAHHA I canโt wait to see what dating is like in 10 years ohhhh man itโs gonna be so fucked for everyone haha bright future weโre bringing forth here