HNR, It is time to watch the British comedy "waiting for God". You will get lessons in proper use of a cane. Apply those to the PT who is such a jerk.
I have several invisible disabilities. My docs insisted that I get a placard and use it. My bones are dissolving painfully, which when added to the arthritis, psoriasis sores, and fibro, hypothyroidism and migraines means I am pretty much SOL in the health dept. I have had a few people challenge me, the worst was a lady at the elem school. She actually STOLE my first tag. I know because I had the number written down in a notebook just in case and saw it in my purse. She wanted it because it is just "so hard" to get into the school with her preschooler from the regular parking spaces. Her child has NO health problems except a mother with an arrest for stealing a placard. One of our dad's is a cop and takes his son to school in the squad car, so when I saw MY placard in HER window, I parked behind her car so she couldn't leave and had the secretary page him. He ran the number of the placard and sure enough, I was right. She had a couple of other warrants so she went bye bye in cuffs and her car went bye bye on a tow truck to the impound lot. Our cops don't play with handicapped parking.
I like Star's letter. I have been judged by many and even been cursed out and followed all over a store with a lady gritching at me. I finally told her to either leave me alone or call the cops and report me for fraud. I also let her know that if she did call the cops and was wrong that I would sue her and own her very fancy car and her very fancy house (knew her by sight from around town and that she is quite wealthy). I told her that I do not have to justify using the placard to ANYONE but my doctor. I fought against getting one but my docs told me it was going to happen and to hoover it up and get on with life. I am glad they did because it makes a difference in how I can get around.
We also get people upset because we have Jess use the motorized carts at the store when we are there. She is just too unsteady on her feet, NOT for lack of trying. Crutches don't help when you are falling because seizures, esp when the docs will give you NO medications even though they SEE the seizures. the neuro saw several in one appointment, even said they were seizures, even saw her fall from one, and still refused to give seizure medications. We have a new family doctor who is working to get us into a new neuro because this is BS.
I tell those people who fuss about J that she was hit by a car 2 times and has bad knee problems. She does. One knee is much larger than the other and nothing seems to help. The ortho docs say it is just going to be a problem fro the rest of her life, which makes me angry. One said he could clearly see impact from 2 different accidents, even though the ER doctor said she made up the accident (grrrrr). Anyway, other than Star's letter, do NOT let that PT fool take away your LEGAL RIGHT to use that space whenever you are there and choose to use it.
If the building mgr says anything, tell him that it is your LEGAL RIGHT to use that space/placard and anything he does to interfere with that is a violation of your rights and you would be happy to have him speak to your atty - and pay the fees for both his and your attorneys for his specious claims.