Not just Apple and Google
My kids aunt bought her a Kindle Fire last year as a birthday present (a Kindle Fire for a seven-year-old, really?). Anyway, you can't actually set it up (or at least if you can, I never found out how, though TBH I didn't look that hard) without entering a credit card number for Amazon - i.e. a credit/debit card is REQUIRED to be able to use it (even if you're only ever going to download the free stuff!)
Yes, I will concede that the security settings for the Kindle are actually fairly good (require password for purchases, eBooks, videos, etc), but how long will it take for you to get so fed up with keep typing in your password you start getting lax and get caught out by them shoulder-surfing you enough times to figure it out? (my 3yo managed to figure out the PIN for my other half's mobile for crying out loud!)
I got around this by using a "test" credit card number when setting up the Kindle, so although it is accepted during the setup phase, it could never be used, even accidentally, for an actual purchase.
There is no two ways about this - in our ever-advancing "gadget" age, kids of all ages are going to be using more and more online devices, be they tablets, phones, watches, Glass and it's ilk, or whatever.
What we really need is for someone (i.e. "app" store operators) to allow for pre-charge "wallets", totally separated from the account tied to the store, that can be topped up periodically (say once a month) and have their own logins - now my kids can have their own apps on their tablets etc (or even on my phone, it wouldn't matter with this setup), with their own capped spending amount, which means they could have some of their pocket money etc put into their accounts that they can blow on whatever flappy-moshi-furby-princess games they want, without it resulting in me not having enough money left at the end of the month to pay the mortgage.
Yes, I realise I could do this with a whole bunch of prepay credit cards, but:
a) why would I want the additional hassle?;
b) technically they are legally too young to use them (although they are prepay cards, I believe they are still covered under the Consumer Credit restrictions - IANAL);
c) depending on how poorly the store is set up (there are plenty of other stores around too), there is still the possibility of over-charge to the card; and
d) their own "wallet" logins would allow them to share, buy things for each other and their friends, and (hopefully!) learn a little more about managing money in our ever more online instantaneous world.. (hey now this is an educational tool too!)
Either that, or they can only have an Etch-a-Sketch until they're 18?