There are strict people like parents or some girlfriends who don't want their kids or boyfriend to play musical instrument, so people with strict parents, or girlfriend may hide their electronic musical instruments until they figure out how to tell them about their hobby for playing music without causing too much disagreements.
I think most types of electronic instruments like electric Piano/keyboard and smaller size electric guitar maybe easier to hide than similar acoustic musical instruments like Piano which look more difficult to control the volume because a real piano uses a small hammer hitting a string inside the piano to make a musical note which travel through the air. But, electronic instruments are like computers and radios which have volume level control buttons to set the volume very low, or users can use the headphone jack to use headphones to play music where the music is harder to hear unless the listeners are in the same room, or sitting right next to the person's headphone while he is playing a electrical instruments.
There are smaller sized electric piano, guitar, and other instruments where they are small enough where you can hide them under your bed, behind furniture, in a closet, or inside a regular looking box or suitcase.
I seen a electric guitar which is as small as a small ruler, so you can hide it in a back pack, or shoe box. There are some small musical keyboard/Piano which can connect to a USB port on a PC, so users can hide these music keyboards inside a small box.
I think most types of electronic instruments like electric Piano/keyboard and smaller size electric guitar maybe easier to hide than similar acoustic musical instruments like Piano which look more difficult to control the volume because a real piano uses a small hammer hitting a string inside the piano to make a musical note which travel through the air. But, electronic instruments are like computers and radios which have volume level control buttons to set the volume very low, or users can use the headphone jack to use headphones to play music where the music is harder to hear unless the listeners are in the same room, or sitting right next to the person's headphone while he is playing a electrical instruments.
There are smaller sized electric piano, guitar, and other instruments where they are small enough where you can hide them under your bed, behind furniture, in a closet, or inside a regular looking box or suitcase.
I seen a electric guitar which is as small as a small ruler, so you can hide it in a back pack, or shoe box. There are some small musical keyboard/Piano which can connect to a USB port on a PC, so users can hide these music keyboards inside a small box.