It could have been much worse than that. In one of the VK B&W TV forums, there is a post by VK member radiotron (Johnny the Raster Master) that tells first hand what can and often does happen when a vintage or antique radio or TV is plugged in without changing at least the filter caps, most if not all of which, in vintage sets, are either defective (often shorted, losing value, or both) or are on the way to failure. I'd almost count on the former in '50s and earlier sets; in fact, filter caps that are bad enough to cause AC hum should be replaced ASAP, as they are probably going to short at any time.
Shorted caps, as we know, will overload the power transformer (in sets so equipped) and cause a fire if, for any reason, the set's own fuse or the house fuse does not blow (for example, if the short is a high-resistance one, though most overloads caused by shorted filter capacitors are low-resistance shorts and will, of course, pop the fuse, if present, or cause major damage if there is no fuse
, in a hurry). I am reminded of an article I read in, IIRC, Reader's Digest some years ago, in which a house fire in Cincinnati, Ohio in the early '60s was caused by a thoughtless homeowner who put a copper penny behind a fuse that kept blowing in his fuse box, rather than unplugging the defective appliance or other device that was overloading the line. A major fire resulted; the house sustained very severe and costly damage that could have been prevented had the fuse box been replaced with a breaker panel than cannot be bypassed.