Yes and no. If a sufficient % of users do this, then you're stuck with "I guess I gotta email them since I have no way to measure engagement". Also, keep in min

Yes and no. If a sufficient % of users do this, then you're stuck with "I guess I gotta email them since I have no way to measure engagement". Also, keep in mind that without these pixels, a sender doesn't know what their open rate is. Open rate is a large metric of whether a sender is considered a spammer or not by Gmail and Microsoft. Without these pixels, senders have no way to benchmark their own behavior against the general ecosystem. It's like asking a runner to get better but not telling them their own mile time. Clearly there can be other solutions like if major email providers gave senders aggregate data on the open rate of emails they process for a given sender, but then you get back into the question around if this is tracking etc much like in this thread.