I'll offer support for you IAnon. Yes, you may not have the most eloquent way of conveying your message, but you seem to have a keen interest in making sure your sons are involved in a healthy endeavor and are actually interested in watching them while they participate. With the limited seating you describe, it really is rude for someone to take up more than one seating space for stupid ass crochet shit. Here's hoping the "like to" in DILF becomes a reality for you.
Dojos I Want To Fuck? This is disturbing and crazy. How dare you in an I,A post where children are mentioned and are maybe possibly reading mention this where is your morals I don't know.
Hippy Moms crochet? They bring their kids to Martial Arts Classes? The world has done a flip. I'll bet the little warriors aren't named Sunshine or Rainbow. On a serious note, with the chairs taken up with satchels of knitting hemp and young Einsteins doesn't that offer you the opportunity to sit closer or even share a chair with those DILF's. HIII YAHHS and Boo Yaah.
I think asking nicely for them to move their stuff so you can sit is reasonable. If they get all "Portland offended" by your brazen polite request then you can feel secure they said knitter is the crazy one, not you. Or you can post some passive aggressive rant on I Passive Aggressive, aka I Anonymous.
Flying hurricane kick. Duh.