It might be fun to have a security force around but I'm afraid we wouldn't be able to hire them as bouncers and they wouldn't be able to act like cops.
So the short answer would be go ahead a a business, but no you wouldn't be playing TMP bouncers.
And the long answer...
We can't give non-wizos positions that would single them out as "special" within TMP itself - eg access to non-public areas and the idea of legally enforcing(/pushing) things against other characters.
It' a clash between Freedom of Destiny and the reality of the setting. If a character is supposed to be able to toss someone out or arrest someone within the setting, then to hold the reality of the setting the player of the other character has to go along with it but it would be affecting the player's right to choose what happens to their character.

If we as hosts were to uphold one character's actions over the other player's wishes, frankly we'd be abusing our positions. To give one character/player advantages over others would be playing favorites. That's why although characters may be hired or contracted for work, it's not a permenant position and doesn't give that character/player privileges. A character may well provide a service to TMP for 5 years. Another character may offer a better service and get hired. (Someone may play up and try tampering with things that have nothing to do with their contract and TMP has drops them from the job.)
Does this make sense?
If later on it is decided that having some characters providing services to TMP is unfair, it would get scrapped and characters would just have to try their luck at being on hand just when soething is needed and when there's an obliging host around...
- Pounamu