2018-06-03 22:23 GMT+02:00 Martin Urbanec <martin.urbanec@wikimedia.cz>:

Well, failed sliently?  Again, I run the same bot in cs.wiki and this is what I can see in logs. 
Yes, that's what I wrote in the initial letter with a link to the log. For me, this is quite silent.
But your example shows something important: Dalba's solution is not general enough, either. It will work for abusefilter-warning, but not for SpamFilterError. Or for abuse filters that deny edit.

Of course Pywikibot didn't report it by email, because it will be unexpectable (and, to be precise, Pywikibot do not always have a way to email you - for example, my Pywikibot bot password don't allow emailing (well, maybe it does, I'm not sure, but it isn't required to allow it). 

Pywikibot should have the option to send a mail to the owner, if he/she wants, and setting the e-mail option for the bot account is worth for this purpose.
Of course, it wouldn't be obligatory.
I don't think we could expect bot owners to monitor their logs all the time. Why should a human do the work of a computer?