Motorola has made a big deal out of its customizable Moto Maker feature for the Moto X. There are 18 different backplates, 504 different combinations and, finally, an engraving feature that lets you write anything you want on the back. Well, almost anything. If you try to something nasty like, "Fuck Russell Brandom," then you'll get a polite but firm refusal: "We'd rather you not say that," the site tells you. "How about another try?" (I sympathize.)

"Facebook," for the record, is fine

So far, it’s just a normal profanity filter, but it gets interesting when you try to put "Apple" in and get the same polite response. Try "Google," "Samsung," or "DROID," and you'll be greeted with the same warning as if you'd tried to carve in a swear word. Like any profanity filter, it's a rough tool: anything you try with "Apple" in it will fall victim to the block, including "An Apple a Day" and "Apple Martin-Paltrow," while "Powered by OS X" and "WebOS forever" slip through unscathed. "iPhone," curiously, also makes it through.

Figuring out why "Apple" got tagged as a dirty word is more difficult. The simplest answer is trademark violations. No one other than Apple has the right to put "Apple" on a phone. "Droid" might seem like fair game for Motorola, but it's actually licensed by Verizon, and ultimately owned by Lucasfilm. Even Google, Motorola’s new and scrupulously independent owners, might object to someone slapping their trademark on the back of a phone they didn’t make. "Facebook," for the record, is fine.

Is Motorola really so afraid of litigation?

But if Motorola’s being cautious, it’s more cautious than most of its competitors. The chance of a company being sued over a user-generated trademark is slim to none. Just look at Apple, which will let you engrave anything you like into the back of your iPod and has yet to be hauled into court over it. It might be awkward to see someone put "Droid" on your non-Droid phone, but who would even do such a thing? Is Motorola really so afraid of litigation?

Better guesses include inter-corporate politeness, a hyperactive Standards & Practices department, or plain old-fashioned embarrassment. Overly clever buyers have been a lingering threat to customizable products ever since some wise guy tried to stitch the word "sweatshop" onto a pair of Nike IDs back in 2001. Mortifying things seem to crop up whenever you let people on the internet put words on something, whether you’re Mitt Romney or Apple. Writing one-offs is funny and they get passed around a lot, but for the people who make the products, it can be embarrassing. Unfortunately for Motorola, it’s only slightly better when you find out what they don’t want you to write.