There was an episode of TNG where the Romulans managed to beam an ambassador off a transporter pad through the ongoing transporter stream in an attempt to make it appear that a malfunction had occurred, so it’s definitely something where having a sending and receiving pad on your end can screw around with the sending and receiving pad on the other end.

Also there is at least one episode of DS9 that I can remember where they remove the weapons of all the Jem Hadar while they’re being beamed over.