Yes, I like this idea.

10 is a lot, but here goes.

1) Perhaps avoiding the the letters "e" and "s" would make communication very difficult as they are the two most used letters in the English language. It would require the sub to think of every word so it would be slow and laborious to write a single message - perhaps choosing a less frequently used letter would lull the sub into forgetting to check. The letter can change each day to keep them on their toes. [easy to check just do ctrl F and search for the letter.]

2) Another rule could be to start and end each email/paragraph/sentence (your choice) with "Sir," [Easy to check]

3) Instead of Disney, you could make it a rule that they have to mention a different sex position or sex activity in a relevant sentence at least once each day, ...or an item or clothing, or a toy, or a piece of fruit, or an item of clothing... You can choose a new subject each month as it is surprisingly difficult to think of more than 31 of anything.

4) the sub must send you an email or message at a precise time each day (e.g. midday) - the punishment increases for every minute they are early or late. [Check the timestamp on the email]

5) they must send you a link to a new story or photo or porn video they like, at least once a day. [easy to check]

6) they must email you as soon as they wake, you can decide what goes in the email (e.g. plans for the day) [check the timestamp]

7) they must email you last thing before going to bed (again you can decide what must be in the email) [check the timestamp]

8) If you are using mobile phones - they must call you once a day from a particular room or place (e.g. the bathroom - you can ask them to turn on the water or hand drier or flush to prove it)

9) change the color (or size) of the font in every message. Colour and size may be repeated, but not in two sequential messages.

10) Clever and cunning? You may want to use this one just once a month ... the sub must propose a new commandment by the end of tomorrow.