Thanks for bringing this up. I know that in a future version of SmarterMail the developers plan to really focus on calendaring and address many of the issues at that time. I'm sure they'll need to look into this a bit more, but if a change is needed in the way this is implemented, it'll be addressed in that future version.
One thing to note: while we do try to develop according to RFC, please be aware that these are suggestions and not hard fast rules. That being said, we try our best to accommodate as many protocols and applications as possible, so I'll go ahead and bring this to the developers' attention as well and we'll look into this a bit more.