Pretty much everyone else already covered how I feel.
I do have one other thought though. Are letters put through a different sorting system? I'd be worried by lying and falsely marking something too large as a "letter size" it could be damaged or torn if it goes through any different sort of processing.
Slightly unrelated, but you should never just mail an item in a plain envelope. Shipping is really rough on packages so you should always make sure items are protected (bubble mailer, bubble wrap, padding, etc). Its very frustrating for buyers when things are packed poorly and end up damaged. If you improperly pack and something happens that damage would be on you.
Pretty much everyone else already covered how I feel.
I do have one other thought though. Are letters put through a different sorting system? I'd be worried by lying and falsely marking something too large as a "letter size" it could be damaged or torn if it goes through any different sort of processing.
This is my thought exactly. I don't know if the rules differ in the US but in Australia you can't put items like than in envelopes because they go through sorting machines. I've been on the receiving end of a purchase being sent in an envelope and arriving quite clearly torn open and empty from the item being forced out. Unless it follows their rules or being thin and bendable it's best so send in a parcel/bubble mailer. It doesn't always happen, but when it does it's really annoying because the post office doesn't care about your missing item if you broke their rules.
I do have one other thought though. Are letters put through a different sorting system? I'd be worried by lying and falsely marking something too large as a "letter size" it could be damaged or torn if it goes through any different sort of processing.
Yes! Anything marked as letter rate does go through a sorting machine that is made for flat items only. It can smash a 3-dimensional items or cause the envelope to rip and force the item out. Parcel rate items even in envelopes will go through a different sorting process & are less likely to be damaged by machines.