Hi Colin

While a 8-11 pass is not in itself a HUM what must inevitably go with it, that is “an opening 1-suit bid which may be weaker than a pass” is DEFINITELY a HUM (second example of Yellow systems in the Manual).

[Unless all 0-7 hands are opened at the 2-level (or 1NT) which I think is unheard of]

There is a system called “Little Spade” which has (something like) this structure for opening bids in first or second position

1C = 16+ Precision style

1D and 1H are transfers showing Precision style 1H or 1S openings respectively

2C and 2D are natural 5+ card suit 12-15 (or 11-15)

1NT and higher openings are “normal”

Notice 1S has been left out
THAT shows 0-7 points
and is a HUM of course AND the rules regarding HUMs must be complied with
That includes providing a full description of the system to the opponents with enough time for them to fully digest it and prepare a defence against it

It's an opening pass that shows not enough hcp to open at the 1 level. That sounds like a normal pass to me. If they preempt 4 card suits 0-7hcp then pass necessarily becomes 8-11hcp. The alert is just there so to inform opponents, it's not artifical.

As for defence against it, how do you defend when anyone else passes showing 0-11hcp? Do what you do over that and you should be just fine.

If you wanted to try something interesting you could try X as 12+ and play 8-11 1 level openers though. No guarantees on results though.

The alternative option is that the pair play something like a 2M 0-7 5+ and 2c catch-all for the other 0-7hcp which would be brown sticker rather than a HUM. You are allowed have a written defence to brown sticker components, however your opponents are under no obligation to provide one.

It doesn't sound like a normal pass to me if it guarantees at least 8 HCP

And whatever opening bid is made with 0-7 is either Yellow or Brown Sticker
and neither are permitted at any competition except A-points AND at least 8 boards per round 

I think the bit "you could try X as 12+ and play 8-11 1 level openers" should be clarified
It looks like an admissable double is being suggested

0-7hcp and 4+suits at the 2 level are red only (although technically blue in current version of manual when combined with strong club/diamond) as they show a suit. Opening these at the 1 level would be considered yellow and opening at the 2+ level without a known 4+suit would be brown. It's really just a (very) bad weak 2 after all.

I said if you want to try something interesting you could X, I didn't say it was legal. Besides, you'll only ever do it once. ????

Who plays the hand if the bidding goes pass (showing opening values) double all pass?
and what is the score?

Oddly, Law 77 does actually allow this calculation to be done. You contracted for no tricks, none score, you didn't make a partscore, but you were doubled so 50. But yeah, this X is inadmissible. 

In the past, I have played:

pass as 13+,

pass as 8-11 54+ or 45+,

pass as 15-19 Bal or 15-19 No 4cM unbal or 20+ any,

pass as 0-6 with an A or 7-10 any.

The number of people who try to X this is quite amazing. But even if you could double, it would be unclear what X would show.

Cheers,

Jack James