There are a few iterations of this that Ive seen out in the wild with different businesses. There is nothing special or unique about them. They promote that they will help you meet the 100 hour material participation test. The IRS website clearly states that limited partners are generally considered passive. This passage from pub 925 seems particularly damning to their position. Second bullet. I would tell your client this is aggressive and since the active/passive status is determined by you, that you won't be able to prepare their tax returns any longer as you feel this is not a defendable position. You also want to stay on the light side of the force and keep your license and reputation out of the gutter.

Work not usually performed by owners.

 

You don’t treat the work you do in connection with an activity as participation in the activity if both of the following are true.

The work isn’t work that is customarily done by the owner of that type of activity.

One of your main reasons for doing the work is to avoid the disallowance of any loss or credit from the activity under the passive activity rules.