If they are permitted to be the pilot in command then you have in effect told them that they do not require a check, training or anything else. If you had check requriements then they would have to be complied with before the pilot could be in command of the aircraft.
Having authorised them to be pilot in command of your aircraft then even if you insist on having one of your friends in the right seat, they as pilot in command have total control of how the flight proceeds. Your friend can not in any way prevent them from flying as they please, to where they please because your friend is not pilot in command and have absolutelty no authority to prevent anything on the flight.
Oh man, that's the best circular argument I've seen in a while.
But where it breaks down is here:
As the owner of an aircraft I can definitely set limits as to when and what the hirer is allowed to do with it. I can for instance, require the hirer to be back by noon, because I want to go flying myself in the afternoon. Or I can prescribe certain operational standards such as RPMs and MPs to use. Or ask the hirer to wear pink shorts. I can also forbid them to do a cross channel flight even though the hirer has an internationally recognised license. Maybe because I'm too cheap to take out insurance covering international flights, maybe because there's a 50 hour check coming up in a few hours and I have a great deal with a local engineer. Who knows. It's my aircraft and I set limits on what others can do with it. If you don't agree to those rules, well, you're very welcome to go elsewhere. A club check is just one of those rules. You break 'em, you go elsewhere.
But as long as you stay within the rules you can be Pilot in Command. Even on a clubcheck.