Well, not precisely. A loss of 3 dB (typical of a 2-way hybrid splitter) is enough to send a marginal yet completely watchable DT signal completely off the cliff. But a signal that close to the edge really should have some amplification for reliability. At any point in time you either have a good picture or you have a bad or no picture. When marginal, that state can change rapidly, and a small loss in level can be catastrophic.
But most signals are not marginal. Note your signal quality reading first. Then add the splitter. In most cases the reading will not go down. If it does, yes, an amp is then a very good idea. If it goes up instead, you probably are using a HR10-250 and are benefitting from the attenuation.