This has been a really interesting thread for me... We're about to do our first WDW trip next September and as Brits, tipping seems to be a bit of a 'minefield'. In general I've found tipping is discretionary over here and usually based on levels of service and more for the 'above and beyond' even in most restaurants and cafe's its not obligatory for a service charge as it seems to be in the states. EU law is now trying to force employers of waiting staff into enforcing set basic wages which don't drop to allow for tips to make up to minimum wage and I agree.
For example, perhaps its the British way but I would feel really uncomfortable and condescending to hand someone a tip into their hand (we usually leave an envelope or pop it on the bedside table). It would feel like bribery or pity to me, but its probably just part of the British psyche. The only people I ever hand money to are homeless people who are out on the streets sleeping rough so wouldn't want staff in a hotel or restaurant to think there was a comparison. Not that I feel that homeless people should be looked down on or pitied as such, just want to money to have a hot bite to eat, but I'm sure you get what I mean... some staff are touchy and would probably take offence.
Recently at DLP however, we tipped generously at more than a few restaurants and heftily so at two for 'above and beyond' levels of service for my daughters birthday and when she had a total meltdown and had to leave the restaurant at short notice. We tipped for portering and left a tip for housekeeping. Likewise however, we have stayed at UK hotels and not left tips for housekeeping... we've always found its not the 'done thing'. Its not that we couldn't afford, just that we didn't want to make anyone uncomfortable at us showing them 'charity'. Its more common here to recognise their efforts in the feedback form or write and thank them for their assistance. Even when tipping in restaurants, we leave it under a plate when we leave (but maybe thats just the stingy Scot in me that doesn't want anyone else snaffling it when they walk past the table and notice it lying there...).
I therefore don't blame those who don't tip, its really a matter of discretion and there is a lot of logic to their arguments about what staff deserve tipping and who don't. What seems clear is that some people rationalise their tipping practice by their heads and others do it by their heart. I say whatever sits best with you, just do it... I don't however like being guilted into it when I've received bad service. I generally would either refuse to tip or complain to get reimbursement for service charge I genuinely felt wasn't warranted. Thought thankfully I've never had to do that to date and hopefully won't at WDW...
When we go, we will probably tip more than usual and as long as I receive a decent standard of service as I feel when we are on holiday we want to spread the joy of being on holiday and thank those who make that a smooth and enjoyable holiday (and hope it will also make mousekeeping (love that name!) receptive to lots of these towel animals I've been reading so much about!). I think they're adorable and show a lot of thought and that special memorable pixie dust I've come to enjoy from Disney holidays...
P.S. What exactly is a 'turndown' service? Don't think they have that over here... is it like when my Mum pops a hot water bottle cover under my duvet for me when I'm ill
? Also is it something thats only available at club/concierge level? Sounds very posh and looking for lots of little unique ways of treating myself on my first of hopefully many 'trips of a lifetime'...
) and my room is clean then I give them 5-10 bucks depending on how much of a mess my kids left which is usually not much. 
