Security Question - Letting someone else install plugins

[RodG]

Im curious tho. is there an additional security threat:

(1) is he/she changes any of the file permissions at a later date?

Any reduction in file permissions will always increase the risk of threats.

(2) isnt my database password stored in one of the config files also.

Yes.

is this a threat?

Only if the wrong people/person has access to it.

Should I go to the effort of changing this also?

Do you go to the effort of locking your windows as well as your doors when you go out? (Sometimes I do, sometimes I don't. Only I am in the position to determine the risk in any given situation).

Cheers
Rod