Forgetting for a moment about the stated fact that language evolves, would Germans be annoyed if a strong verb was used as it were weak (that is, with the common -te pattern in the past tense and the ge- prefix in the past participle)?
Moreover, would this usage affect comprehension of what the person is saying, and to which level?
As an example, imagine that I say
Gestern gehte ich ins Kino.
Gestern ging ich ins Kino.
This is something that in English happens all the time, with no particular comprehension problems, does the same stand for German?