What terms and conditions would those be? If I visit PPRuNe without being logged in I'm presented with advertising without agreeing to anything. If I join PPRuNe there is no mention of requiring the display or viewing ads in the terms and conditions. I checked. What I choose to display on my screen or download is entirely at my discretion.
The reputation of the company says very little about the reputation of the ads being served - many reputable companies have served dodgy ads because they do nothing to vet the adverts that appear on their website by entirely outsourcing advertising to third parties.