Legal Question in Intellectual Property in California

They owe the songwriters a "mechanical license fee" of a few cents every time the music and lyrics are "performed." It's a copyright infringement, but it's much less expensive, and much less likely to get the performer in legal trouble than infringing a performance (a recording of someone, such as the original artist, singing the song). Also, unlike a sound recording of a musical performance, the copyright holder(s) in the music and lyrics do not have the right to prohibit anyone from singing (performing) the song, as long as the mechanical license fee is paid.

It constitutes copyright infringement. Most video sites will not allow such videos to remain posted, and will remove them as soon as they discover this.