Are email read receipts rude?

A couple of people I email on a regular basis request a read receipt by default. I don't send them, partially because I hate the dialog that pops up asking me whether I want to every time I receive an email from them and partially because I'm just plain awkward.

I'd much rather have an SMS style delivery receipt, ie I know it's got there, the transport mechanism has done it's job, I'm happy for the recipient to operate according to their own timescales and tell me when they're ready to respond.

The problem with read-receipts is that they're cross that line into the recipient exposing what they are doing to you. If I read an email, I might want consider a response, I might just be scanning to prioritise and get to it later. Indicating to someone that I've read it implies that I'm working on it straight away and they should ready themselves for a response.

So requesting a read receipt from me will certainly not get a response but you might succeed in raising my blood-pressure slightly ;)