No , the ones that let you in wont follow you around and you can take your time ask or tell them first before removing anything as they may have some parts reserved for someone , I am not American so I don't know how often the American places do it , they go through some cars quicker than others , the kei (660cc turd cars) are very popular so they go through parts quick and get taken to a recycling plant sooner , other cars stay long up to year or two etc. Also depending on the size of the yard ...
Then there will be places who just won't sell to the public and only to their regular customers which are repair shops mechanics , a place near my house ended up like that because they were probably tired of people braking a bunch of stuff to get to the part they were after etc.
Most will let you walk around take your time ask for prices on parts you want and then you go remove them , pay on your way out etc.