Yes! Having long time ago done some minor web scraping, I did not put any work at all into following robots.txt, simply because it seemed like a hassle and I thought "meh it's not that much traffic is it and boss wants this done yesterday". But if the tool defaulted to following robots.txt I certainly wouldn't have minded, it would have caused me to get less noise and my tool to behave better.

Also, throttling requests and following robots.txt actually makes it less likely that your scraper will be blocked, so even for those who don't care about the ethics, it's a good thing to have ethical defaults.