I haven't been around here as long as others - which is to say perhaps take my opinion on this with a grain of salt - but I've noticed I've been flagging a lot of posts about plugins to say they're off-topic.
This is particularly the case with WooCommerce, where often the question is clearly off-topic (asking about WooCommerce specific hooks, or how to add shipping methods, etc.) but also happens to a lesser extent with other plugins.
The woocommerce excerpt says that 'Questions specific for this plugin are off-topic.' This doesn't seem to stop many questions from coming through, but perhaps it does stop those we never see (I don't know, obviously it's impossible to get the data on that).
Given the excerpt pops up when you select the tag, I would suggest that we still include a (short) note in the excerpts that questions specific to these plugins are off-topic. Otherwise, I tend to think we'll get more off-topic questions, because we can't really expect everyone to read (or even visit) the full tag wikis.
(In fact, I only just realised now that the full tag wiki for woocommerce implies - apart from in the excerpt - that we would support this plugin, given it asks for the 'System Status Report' to be submitted with questions. The wiki does mention StackOverflow so it's possible it was copied from there and hasn't been edited for WPSE.)