If you look at the root directory where BootIt BM is installed, you will see several BOOTITBM.*, EMBR*.*, BOOTIT*.SND and *.BBM files along with a small number of other supporting files. If you included Image for DOS with the installation, IMAGE.EXE and several CDBOOT.* files will exist. You will also see the directory \BOOTIT in all Multi-OS partitions.
If BootIt BM is installed to a visible/shared partition, you can hide the BootIt BM files if you would like. Use attrib from the Command Prompt (attrib +h bootitbm.*, attrib +h bootit*.snd, attrib +h *.bbm, etc.) or file properties in Explorer and set the file hidden.