Acceptable? Probably.

True? Not really.

I see no problem at all.
IMHO you are allowed to draw attention to referrals.
It's pay per action, so what?

Acceptable? Probably.
True? Not really.

I've seen multiple very very strange things with sites that validate and look #*$!TY on IE....

Yes, quite a few sites look better and browse better in Firefox....

Except mine. Mine looks crappy on Firefox.

Not sure how many people change their browser anyway. Don't most people use whatever is installed on their PC when they buy it, or whatever the ISP's setup disk installs?

OK - I've got most browsers as an option, but I need to check my site works in them. Most aren't in that situation, and I don't think most would change.

See what AdSenseAdvisor said here:
[webmasterworld.com...]

...in the content of your site you could provide an endorsement for the product you are choosing to refer. For example, you might say, "I recommend the firefox browser."