Grizzly - there is a reason they are level restricted zones. If the game has them, then no one should be allowed in the zone below the given level. If they were to remove the restriction, then I'd be okay with it.
Just because someone wants to focus on crafting, does not mean they should be allowed in a zone that is level restricted. Being able to group summon into an area is an exploit/bug that should be fixed one of two ways. Remove the restrictions or don't allow people below the level restriction. If they want to gather the resources, they can do it in a non-restricted zone with a little more danger to have to deal with.
Bots will happen for sure, and I agree with you on that aspect. However, it's much easier to create a level 1 character to have group summoned in, than leveling up to a certain level to bot. It takes more time in the latter, which could possibly reduce some of the thoughts about botting (ie they don't want to spend the time to level up to the level).
You offer some valid points. I much agree they need to be removed though I say that a little out of context in regards to your post I admit. I will start from the bottom of you post and work up. Even if the group summon was tweaked so that low level players would need to level up so that they could reach new zones that would not eliminate the botting issue. All it would do is create a reason for botting to encompass combat so that the bots could reach the different materials in higher level locked zones which has been done in numerous other games with similar locking systems. It really doesn't matter much to someone who may bot whether they can gain direct access to something or if they need to bot their way to it as they are still not actually putting the work in for themselves. And to add onto this I have yet to see a player who has asked for a group summon into an area bot or caught botting. I think this is once again more of a "what if" type situation.
Next, because someone wants to work on crafting they are quite literally forced to either level up to reach new zones with ripe materials which they can use or choose from the slim pickings left over in zones that do not offer a decent supply of the materials the crafter may require. This is a severely limiting aspect of the game without finding someone to get you to where you're trying to go. As it stands the only real danger a crafter may face is while being in a zone that is level locked and trying to dodge hungry mobs. I don't see this as an exploit/bug but rather a legitimate feature of group summon mainly because it's not harmful if the crafter has the levels to gather the resources but doesn't have the level to actually reach this content. If they get snagged by a mob, they die and suffer the penalty for not being able to keep out of range of the angry critters. Granted I do see where you are coming from in the fact that a crafter would not be able to legitimately reach the zone without the help of another but this is a non-issue to me as it doesn't have any negative impact on any third party in the slightest.
Finally to top off this post, and thank you for reading as I realize it is quite lengthy, the level locking system in itself is something I disagree with and I look at it more as a warning for players because there will be mobs in the zone that are of "X" level so be cautious. Instead it is set up so that a player literally cannot gain access to a zone unless they are at level which is wrong to a fault in my personal opinion. And once again to reiterate there is no harm whatsoever in group summoning a player into a zone for whatever the reason may be as it has zero effect on anyone but the crafter/player his/her self. Granted the final decision of how this is to be interpreted and used comes down to a developers standpoint and word on the issue.