OK but the coils used in a CRT tube just do not produce a magnetic field anywhere near strong enough to affect a tape on a nearby shelf, however close the shelf is. Steering a beam of super-light electrons doesn't take much power.
Plus when the TV is off (most of the time) there is no mag.field produced by these metal coils. They are not permanent magnets - no power, no mag.field. i'm just trying to say that mag.fields produced by a CRT TV will not "easily delete content of tapes on a nearby shelf" at all.
So you don't really have to worry bout that.