as i know crashers are crashers they are not any crashers , but instead they are great crashers..
ok in english :
crashers most of them uses a bug in the game/server that could bug a player or atleast drop his fps , or even they can teleport a player to none covered place in gta sa (unknown coords), so he get bugged since there is nothing to make him get back to the covered place in gta
all i have (that i saw in codes and know how to make) is player bugger (send players to unknown coords)
other than that , i have no idea xD , but usually it is a bug or something coded wrong with "samp" and/or didn't covered in codes that can be injected to do specific functions (in our case crashing)