[SkyBelow]

Having dabbled in kanji, my initial assumption is that such a worry is justified. With English you have 60 or so characters you need to know how to write, many near duplicates (X vs x, U vs u). Kanji is far more numerous and also seems to have a more artistic emphasis.

[SpicyLemonZest]

Yeah, the worry's pretty unambiguously justified; even today, native speakers sometimes just forget how to write words they know. It's just a question of how much it matters.