I find it hard to blame people for bad use of characters that they don't have on their keyboard layouts. I'm French speaking, I don't care if you're not putting an accent on "échelle" when writing to me in a casual conversation, I understand you mean "ladder" when you write "echelle".
Edit: Makes me think, I myself am often just working on something with the US layout at the same time as communicating in French, and not wanting to juggle between layouts, I just skip accents.